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{{Short description|U.S. national memorial in Washington, D.C.}}
{{About|the monument in Washington, D.C.|the monument in Baltimore|Washington Monument (Baltimore)|other uses}}
{{Use mdy dates|date=August 2018}}
{{Use American English|date=October 2013}}
{{Infobox building
| name             = Washington Monument
| image = Washington Monument 2022.jpg
| caption = The Washington Monument in [[Washington, D.C.]], in 2022
| status           = {{green|Completed}}
| highest_prev     = [[Cologne Cathedral]]
| highest_next     = [[Eiffel Tower]]
| highest_start    = 1884
| highest_end      = 1889
| location_town= [[National Mall]], [[Washington D.C.]]
|location_country=United States
| map_type         = United States Washington, D.C. central#Washington, D.C.#USA
| coordinates      = {{coord|38|53|22|N|77|2|7|W|region:US-DC_type:landmark|display=inline,title}}
| floor_count      =
| address = 2 15th Street NW, Washington, D.C., 20024
| start_date       ={{Start date|1848|07|04}}
| topped_out_date  = {{end date|1884|12|06}}
| topped_out=yes
|years_built=1848–1854, 1877–1888
| stop_date = 1854–1877
| completion_date  ={{Start date|1888}}
| groundbreaking_date ={{Start date|1848}}
| renovation_date     = 1992–1993, 1998–2002, 2012–2019
| opening          = {{Start date|1888|10|09}}
| inauguration_date = {{Start date|1885|02|21}}
| owner            = [[National Park Service]]
|grounds_area = {{convert|106.01|acre|ha}}
| height = {{convert|555|ft|m|abbr=on}}
{{collapsed infobox section begin|Other information}}
| roof             = 
| top_floor        = 
| floor_area       = 
|public_transit=[[Smithsonian station|Smithsonian]] [[Washington Metro|metro]] station
| elevator_count   = 1
{{collapsed infobox section end}}
| architect        = [[Robert Mills (architect)|Robert Mills]]
| engineer         = [[Thomas Lincoln Casey Sr.]]
| main_contractor  = [[United States Army Corps of Engineers]]
| cost = $1,187,710
| developer        = [[United States Army Corps of Engineers]]
| references       =<ref name=NGS2015 />{{rp|6, 82, 86}}
| website =  {{URL|https://www.nps.gov/wamo/index.htm}}
|module={{Infobox historic site
| visitation_num = 671,031
| visitation_year = 2008
| governing_body = [[National Park Service]]
| designation1 = NRHP
| designation1_date =  October 15, 1966
| designation1_number = 66000035
| designation2 = NMEM
|embed=yes
}}
}}
The '''Washington Monument''' is a {{convert|555|foot|adj=on}} tall [[obelisk]] on the [[National Mall]] in [[Washington, D.C.]], built to commemorate [[George Washington]], a [[Founding Fathers of the United States|Founding Father of the United States]] and the nation's first president. Standing east of the [[Lincoln Memorial Reflecting Pool|Reflecting Pool]] and the [[Lincoln Memorial]],<ref>{{Citation| title = Foundation Statement for the National Mall and Pennsylvania Avenue National Historic Park| newspaper = [[National Park Service]]| url = https://www.nps.gov/nationalmallplan/Maps/NMMParks_map.pdf |access-date=May 20, 2010}}</ref> the monument is made of [[Gneiss|bluestone gneiss]] for the foundation and of [[granite]] for the construction.<ref name=HABStext>{{cite book |url=http://lcweb2.loc.gov/master/pnp/habshaer/dc/dc0200/dc0261/data/dc0261data.pdf |first=Aaron V. |last=Wunsch |title=Historic American Buildings Survey, Washington Monument, HABS DC-428 (text) |publisher=National Park Service |year=1994 }}</ref> The outside facing consists of three different kinds of white [[marble]], as the building process was repeatedly interrupted.<ref>[https://pubs.usgs.gov/gip/stones/stones4.html '' Washington's Geologic Setting.''], Website [[U.S. Geological Survey]], retrieved on February 13, 2024.</ref> The monument stands {{convert|554|ft|7+11/32|in|m}} tall, according to [[U.S. National Geodetic Survey]] measurements in 2013 and 2014.{{efn-ua | name=height |

Several heights have been specified, all of which exclude the foundation, whose top is {{convert|15|ft|8|in|m}} above the pre-construction ground level. The foundation is surrounded by a grassy [[wikt:knoll|knoll]], which serves as a [[buttress]] for the monument's foundation and effectively places the monument's foundation below ground level.
* {{convert|554|ft|7+11/32|in|m}} according to the National Geodetic Survey (NGS)<ref name=NGS2015>National Geodetic Survey, [http://www.ngs.noaa.gov/PUBS_LIB/NOAA_TR_NOS_NGS_51_2015_02_16.pdf "2013–2014 Survey of the Washington Monument"] {{webarchive |url=https://web.archive.org/web/20160303212025/http://www.ngs.noaa.gov/PUBS_LIB/NOAA_TR_NOS_NGS_51_2015_02_16.pdf |date=March 3, 2016 }}, 2015. Horizontal coordinates converted from NAD83(2011) to WGS84(G1674), the required coordinate system for Wikipedia coordinates, via [http://www.ngs.noaa.gov/cgi-bin/HTDP/htdp.prl?f1=4&f2=1 NGS Horizontal Time-Dependent Positioning], epoch 2010.0 including ellipsoidal height.</ref>{{rp|5}} using the criteria of the [[Council on Tall Buildings and Urban Habitat]] (CTBUH), that is, from the "level of the lowest, significant, open-air, pedestrian entrance" to the highest point of the building.<ref name=CTBUH>{{cite web|url=http://www.ctbuh.org/TallBuildings/HeightStatistics/Criteria/tabid/446/language/en-US/Default.aspx|title=CTBUH Criteria for Defining and Measuring Tall Buildings|work=ctbuh.org}}</ref> From among four candidate points suggested by the NGS, the CTBUH chose a point on the entry ramp installed in 1975 where it crosses the outer face of the marble facade of the monument.<ref name=HABStext />{{rp|7}}<ref name=NGS2015disagree>National Geodetic Survey, [http://www.ngs.noaa.gov/surveys/ngs/wm2013/2015%2002%2016%20Architectural%20Height%20Difference%20Explanation.pdf "Why does the value obtained in 2014 ... disagree with the 1884 value ...?"] {{webarchive |url=https://web.archive.org/web/20160304130507/http://www.ngs.noaa.gov/surveys/ngs/wm2013/2015%2002%2016%20Architectural%20Height%20Difference%20Explanation.pdf |date=March 4, 2016 }}, 2015, picture of precise spot used.</ref><ref name=HSR />{{rp|2{{hyphen}}15, 3{{hyphen}}18, 4{{hyphen}}13, B{{hyphen}}49, <!-- This ref uses page within chapter numbering, so page 2-15, for example, means page 15 within chapter 2, NOT pages 2 to 15. Chapters 1, 3 and 4 all have a page 15. --> figs 3.32, 3.33, 3.39, 3.42}}<ref name=HABSdrawings />{{rp|sheet 31}} Measured 2013–14 and reported {{nowrap|February 16, 2015}}. This is also its new above-ground height because the ground at the shaft was raised in 1975 to match the ramp. The ground surrounding the shaft was replaced by granite pavers during 2004–05 to match the raised ground level and the ramp. This height is {{convert|22.0|cm|in|frac=8|sp=us}} above four "CASEY marks", {{convert|2+1/2|in|cm|adj=mid|-diameter}} brass bolt heads whose shafts are inserted vertically into the topmost level of the foundation just outside the four corners of the monument. These CASEY marks were set flush with the lower surface of the marble blocks. The NGS thinks they were likely used by Col. Thomas Lincoln Casey, the engineer in charge of construction, to determine the traditional height in 1884. The floor at the elevator is now {{convert|13.9|cm|in|frac=8|sp=us}} above this pedestrian entrance, and {{convert|35.9|cm|in|frac=8|sp=us}} above the CASEY marks.<ref name=NGS2015 />{{rp|13, 56, 65, 82–84}} The highest point of the monument is a one-millimeter-diameter dimple atop the aluminum apex.
* {{convert|555|ft|5+1/8|in|m}} according to the [[National Park Service]].<ref name=FAQ>{{cite web|url=https://www.nps.gov/wamo/faqs.htm |title=Frequently Asked Questions about the Washington Monument by the National Park Service |publisher=Nps.gov |access-date=January 31, 2013}}</ref> Measured and reported in 1884 by Col. Thomas Lincoln Casey, the engineer in charge of construction.<ref name=Casey1884>Thos. Lincoln Casey, "report of operations upon the Washington Monument for the year [1884]" in [http://infoweb.newsbank.com/iw-search/we/Digital/?p_product=SERIAL&p_theme=sset2&p_nbid=U64Q5BHYMTQyMzY5Njg4NS44MDg5ODg6MToxNToxMzIuMTcwLjIwOC4yMjQ&p_action=doc&p_docnum=10&p_queryname=7&p_docref=v2:0FD2A62D41CEB699@SERIAL-10EA77401B2FA010@-@0 ''Letter from William W. Corcoran, Chairman of the Joint Commission for the Completion of the Washington Monument, transmitting the annual report of the Commission, December 19, 1884'']{{cbignore}}, U.S. Congressional Serial Set, Vol. 2310, 48th Congress, 2nd Session, House of Representatives Misc. Doc. 8, p. 5. Available for free in most large United States libraries in government documents or online. Establish a connection to [http://www.readex.com/log-through-your-library ''Readex'' collections] before clicking on link.</ref> It was measured from the top of the foundation (the lowest marble joint or the door-sills of the two empty doorways), which was in place in 1884. This is the traditional height of the monument that became moot when the pavement or ground next to the monument was raised in 1975.
* {{convert|554|ft|11+1/2|in|m}} according to architectural drawings in the ''Historic American Buildings Survey'' (1994), pavement at shaft to tip.<ref name=HABSdrawings>{{cite book |url=https://www.loc.gov/pictures/item/dc0261/ |title=Historic American Buildings Survey, Washington Monument, HABS DC-428 (drawings)|first1=Robert R. |last1=Arzola |first2=Dana L. |last2=Lockett |first3=Mark |last3=Schara |first4=Jose Raul |last4=Vazquez |publisher=National Park Service |year=1994 }}</ref>{{rp|sheets 7, 31}} This height is comparable to the NGS height because it was also determined after the ramp was installed in 1975.
None of these heights include a set of [[lightning rod]]s surrounding the monument's aluminum apex. An old set was installed in 1934, which protruded above its tip by {{convert|6|in|cm}}.<ref name=Binczewski /> In 2013 a new set of lightning rods was installed which protrude above the apex by about {{convert|1|ft|m|1|spell=in}}.<ref name=NGS2015 />{{rp|23, 26}}<ref name=AerialAmerica>{{cite episode |title=Aerial America: Washington D.C. |series=Aerial America |url=http://www.smithsonianchannel.com/shows/aerial-america/701 |network=Smithsonian channel }}{{dead link|date=August 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
}} <!-- end of efn-ua --> It is the third tallest monumental column in the world, trailing only the [[Juche Tower]] in Pyongyang, and the [[San Jacinto Monument]] in Houston, Texas.{{efn-ua | name=columns |

Only two other monumental columns honoring a person or thing have heights comparable to that of the Washington Monument: the [[San Jacinto Monument]] in Deer Park, Texas, and the [[Juche Tower]] in Pyongyang, North Korea. Which of the three is tallest depends on how its height is measured.<ref name="Kelly">{{cite news |url=https://www.washingtonpost.com/local/the-washington-monument-is-tall-but-is-it-the-tallest/2013/06/19/93665ae6-d8ee-11e2-a9f2-42ee3912ae0e_story.html |title=Local: The Washington Monument is tall, but is it the tallest? |first1=John |last1=Kelly |date=June 19, 2013 |newspaper=[[Washington Post]] |access-date=December 26, 2016}}</ref> A traditional method is above a part of the monument comparable to ground level. A more recent method is that used by the [[Council on Tall Buildings and Urban Habitat]] (CTBUH), the arbiter of the height of tall buildings since 1969. CTBUH states the height of a building must be measured above the "level of the lowest, significant, open-air, pedestrian entrance".<ref name=CTBUH /> Under this measurement, the Washington Monument is the tallest, followed by the San Jacinto Monument at {{convert|-2.6|ft|m}} and the Juche Tower at  {{convert|-6|m|ft|sp=us|order=flip}}. The above-ground heights of the three monumental columns from tallest to shortest are the San Jacinto Monument ({{convert|+12.70|ft|m|3}}), the Juche Tower ({{convert|+1|m|ft|sp=us|order=flip}}), and the Washington Monument. Height differences are relative to the height of the Washington Monument.
* The Washington Monument's CTBUH (above pedestrian entrance) height, {{convert|554|ft|7+11/32|in|m}}, is the same as its above ground height.
* The San Jacinto Monument has a surveyed height of {{convert|567.31|ft|m|3}} from its footing to the top of its beacon. However, the architect of the monument, Albert C. Finn, stated, "San Jacinto ... is actually {{convert|552|ft|m|1|disp=sqbr}} from the first floor to the top of the beacon" ... in the "customary way" of measuring such things.<ref name=SanJacinto>Paul Gervais Bell Jr., [http://texashistory.unt.edu/ark:/67531/metapth101220/m1/40/ "Monumental Myths"]  {{webarchive|url=https://web.archive.org/web/20160304002103/http://texashistory.unt.edu/ark%3A/67531/metapth101220/m1/40/ |date=March 4, 2016 }}, ''Southwestern Historical Quarterly'', vol. 103, 2000, frontispiece–14, pp. 13–14</ref> The "first floor" is the CTBUH criterion. A stepped [[terrace (building)|terrace]] elevates this pedestrian entrance above ground, thus reducing the monument's remaining height by its thickness, about {{convert|15.5|ft|m}}, to the monument's CTBUH height. The monument is made of reinforced concrete, not stone, although it has a facade of limestone.
* The Juche Tower has a specified height of {{convert|170|m|ft|0|sp=us|order=flip}} above a very large concrete bus parking lot just east of the tower. A stepped terrace elevates its pedestrian entrance, also on its east side, above this ground level. Its thickness, {{convert|7|m|ft|sp=us|order=flip}}, reduces the remaining height of the tower to {{convert|163|m|ft|sp=us|order=flip}}, its CTBUH height. The tower is made of reinforced concrete, not stone, although it has a facade of granite. A metal cage holding many panels of red glass in the shape of a flame, internally illuminated, surmounting a gold-colored "fuel chamber", occupies its top {{convert|20|m|ft|sp=us|order=flip}}.}}<!-- end of efn-ua columns --> It was the world's tallest structure between 1884 and 1889, after which it was overtaken by the [[Eiffel Tower]], in Paris.

Construction of the [[Presidential memorials in the United States|presidential memorial]] began in 1848. The construction was suspended from  1854 to 1877 due to funding challenges,<ref>[https://penelope.uchicago.edu/Thayer/E/Gazetteer/Places/America/United_States/US_Government/_Texts/House_of_Representatives/33d_Congress/2d_Session/Report_No94*.html ''US House of Representatives, 33d&nbsp;Congress, 2d&nbsp;Session, Report No.&nbsp;94''], as transcribed in Thayer's Gazetteer, retrieved on February 7, 2025.</ref> a struggle for control over the Washington National Monument Society, and the [[American Civil War]]. The stone structure was completed in 1884, and the internal ironwork, the knoll, and installation of memorial stones was completed in 1888. The original design was by [[Robert Mills (architect)|Robert Mills]] from [[South Carolina]], but construction omitted his proposed [[colonnade]] for lack of funds, and construction proceeded instead with a bare obelisk. The completed monument was dedicated on February 21, 1885, and opened to the public on October 9, 1888. In 2001, a temporary security screening facility was added to the entrance. Following the [[2011 Virginia earthquake]], the monument was closed for repairs until 2014, and it was closed again from 2016 to 2019.

The Washington Monument is a hollow [[Ancient Egyptian architecture|Egyptian]]-style stone [[obelisk]] with a {{convert|500|ft|m|1|adj=mid|-tall}} column surmounted by a {{convert|55|ft|m|1|adj=mid|-tall}} [[pyramidion]]. The walls taper as they rise and are supported by six arches; the top of the pyramidion is a large, marble capstone with a small aluminum pyramid at its apex, with inscriptions on all four sides.<ref name=Torres /> The interior is occupied by iron stairs that spiral up the walls, with an elevator in the center. The pyramidion has eight observation windows and eight red aircraft warning lights, two per side. At the northeast corner of the foundation is a marble [[cornerstone]], including a [[zinc]] case filled with memorabilia.<ref name="Torres" /> Fifty U.S. flags fly on a large circle of poles centered on the monument,<ref name="flags" /> representing each U.S. state. 

==History==
[[File:LCCN2003656330 Design of the National Washington Monument in the City of Washington cropped.jpg|thumb|upright=1|Print of the proposed Washington Monument by architect [[Robert Mills (architect)|Robert Mills]], {{Circa|1845}}–1848|left]]
The monument was built to honor [[George Washington]], the first [[president of the United States]].<ref name="Freeman g620">{{cite journal |last=Freeman |first=Robert Belmont |year=1973 |title=Design Proposals for the Washington National Monument |url=http://www.jstor.org/stable/40067740 |journal=Records of the Columbia Historical Society, Washington, D.C. |publisher=Historical Society of Washington, D.C. |volume=49 |pages=151–186 |issn=08979049 |jstor=40067740 |access-date=November 8, 2025}}</ref>{{Rp|151}} At Washington's death in 1799, he was the unchallenged public icon of [[United States Armed Forces|U.S. military]] and [[civic patriotism]]. He was also identified with the [[Federalist Party]], which lost control of the national government in 1800 to the [[Democratic-Republican Party|Jeffersonian Republicans]], who were reluctant to celebrate the hero of the opposition party.<ref>{{cite book|author=Paul K. Longmore|author-link=Paul K. Longmore|title=The Invention of George Washington|url=https://books.google.com/books?id=wTOXSRg8jD4C&pg=PA207|year=1999|publisher=Univ. of Virginia Press|page=207|isbn=978-0-8139-1872-3|access-date=February 16, 2015}}</ref>

===Proposals===
After the [[American Revolutionary War]], there were many proposals to build a monument to Washington, beginning with an authorization in 1783 by the old [[Congress of the Confederation|Confederation Congress]] to erect an equestrian statue of the general in a future U.S. national capital city.<ref name=":0">Sheldon S. Cohen, "Monuments to Greatness: George Dance, Charles Polhill, and Benjamin West's Design for a Memorial to George Washington." ''Virginia Magazine of History and Biography'', April 1991, Vol. 99 Issue 2, pp. 187–203. {{JSTOR|4249215}} {{ISSN|0042-6636}}. Retrieved February 16, 2015.</ref><ref name="Freeman g620" />{{Rp|151}} The initial proposal called for an [[equestrian statue]].<ref>George Cochrane Hazelton, ''The national capitol: its architecture, art and history'' (1902) p. 288.</ref><ref name="Freeman g620" />{{Rp|151}} 

On December 24, 1799, ten days after Washington's death, a U.S. congressional committee recommended a different type of monument. U.S. representative [[John Marshall]] proposed that a tomb be erected within the [[United States Capitol|Capitol]], but a lack of funds, disagreement over what type of memorial to build, and the Washington family's reluctance to move his body from [[Mount Vernon]] prevented progress on any project.<ref name="wash">{{cite news
| url=http://www.cr.nps.gov/nr/twhp/wwwlps/lessons/62wash/62wash.htm
| publisher=National Park Service, ParkNet
| title=The Washington Monument: Tribute in Stone
| access-date=April 27, 2006
| archive-date=December 25, 2016
| archive-url=https://web.archive.org/web/20161225083027/https://cr.nps.gov/nr/twhp/wwwlps/lessons/62wash/62wash.htm
| url-status=dead
}}</ref> The [[Democratic-Republican Party]] (Jeffersonian Republicans) took control of Congress in 1801 and rescinded prior approvals for the memorial.<ref name=":0" /> Further political squabbling, along with the American Civil War, blocked the completion of the Washington Monument for much of the 19th century.<ref>Kirk Savage, ''Monument Wars: Washington, D.C., the National Mall, and the Transformation of the Memorial Landscape'' (2009) pp. 32–45</ref>

===Design===
[[File:Washington National Monument Society 1845.jpg|thumb|Donation receipt of the Washington National Monument Society|left]]
Progress toward a memorial finally began in 1833, when a group of citizens formed the Washington National Monument Society.<ref>{{cite magazine |first=John |last=Lockwood |date=Spring 2016 |url=https://www.archives.gov/files/publications/prologue/2016/spring/monument.pdf |title=The Men—and the Women—Who Built the Washington Monument |magazine=[[Prologue (magazine)|Prologue]] |publisher=National Archives |access-date=February 26, 2025}}</ref> On September 23, 1835, the board of managers of the society described their expectations:<ref name="nps3">{{cite web |url=http://www.nps.gov/NR/twhp/wwwlps/lessons/62wash/62facts4.htm |archive-url=https://web.archive.org/web/20070901072132/http://www.nps.gov/nr/twhp/wwwlps/lessons/62wash/62facts4.htm |url-status=dead |archive-date=September 1, 2007 |title=The Washington Monument: Tribute in Stone, Reading 3 |publisher=National Park Service |access-date=August 12, 2011}}</ref>{{blockquote|It is proposed that the contemplated monument shall be like him in whose honor it is to be constructed, unparalleled in the world, and commensurate with the gratitude, liberality, and patriotism of the people by whom it is to be erected&nbsp;... [It] should blend stupendousness with elegance, and be of such magnitude and beauty as to be an object of pride to the American people, and of admiration to all who see it. Its material is intended to be wholly American, and to be of marble and granite brought from each state, that each state may participate in the glory of contributing material as well as in funds to its construction.}}

In 1836, after they had raised $28,000 in donations ({{Inflation|US-GDP|28000|1835|r=-6|fmt=eq}}), they announced a competition for the design of the memorial.<ref name="Olszewski">{{cite web |last=Olszewski |first=George J. |year=1971 |title=A History of the Washington Monument, 1844–1968, Washington, D.C. |url=http://npshistory.com/publications/wamo/history/index.htm |publisher=National Park Service |location=Washington, D.C.}}</ref>{{rp|chp 1}} [[Robert Mills (architect)|Robert Mills]] was formally selected in 1845.<ref name=HSR />{{rp|2{{hyphen}}2}} Mills had previously designed a [[Washington Monument (Baltimore)|monument to George Washington]] in nearby Baltimore in 1815, and he had been just been chosen Architect of Public Buildings for Washington. His design called for a circular colonnaded building {{convert|250|ft|m}} in diameter and {{convert|100|ft|m}} high, supporting a four-sided obelisk {{convert|500|ft|m}} high, for a total height of {{convert|600|ft|m}}. A massive cylindrical pillar {{convert|70|ft|m}} in diameter would support the obelisk at the center of the building. The obelisk was to be {{convert|70|ft|m}} square{{efn-ua | name=Obelisk1836 | The base of the obelisk atop the circular pillar was to have been "70 feet square" ({{convert|70|ft|m|disp=out}} square) according to the House report of 1872<ref name=House1872 />{{rp|8}} and Torres (1984),<ref name=Torres />{{rp|13}} but only "50 feet square" ({{convert|50|ft|m|disp=out}} square) according to Harvey (1903).<ref name=Harvey />{{rp|27}} The corners of a {{convert|70|foot|m}} square base ({{convert|99|foot|m}} diagonal) would dangerously overhang a {{convert|70|foot|m}} diameter pillar, whereas a {{convert|50|foot|m}} square base ({{convert|71|foot|m}} diagonal) would not. <!-- end of efn-ua --> }} at the base and {{convert|40|ft|m}} square at the top with a slightly peaked roof. Both the obelisk and pillar were hollow within which a railway spiraled up. The obelisk had no doorway—instead its interior was entered from the interior of the pillar upon which it was mounted. The pillar had an "arched way" at its base. The top of the portico of the building would feature Washington standing in a chariot holding the reins of six horses. Inside the colonnade would be statues of 30 prominent [[American Revolutionary War|Revolutionary War]] heroes ands statues of the 56 signers of the [[United States Declaration of Independence|Declaration of Independence]].<ref name=House1872>[http://www.infoweb.newsbank.com/iw-search/we/Digital/?p_product=SERIAL&p_theme=sset2&p_nbid=O5FV50BLMTQ5MjYyMDcxOC4zOTU0MjoxOjE0OjEzMi4xNzAuMjcuMjU1&p_action=doc&p_docnum=752&p_queryname=9&p_docref=v2:0FD2A62D41CEB699@SERIAL-10B351852A1112D0@-@0 Washington National Monument, April 19, 1872]{{cbignore}}, U.S. Congressional Serial Set, Vol. 1528, 42d Congress, 2d Session, House Report 48. Available for free in most large United States libraries in government documents or online. Establish a connection to [http://www.readex.com/log-through-your-library ''Readex'' collections] before clicking on link.</ref>{{rp|6–8}}<ref name=Torres />{{rp|13}}<ref name=Harvey />{{rp|26–28}}

Criticism of Mills's design came up already in 1847, when architect Henry Robinson Searle from Rochester presented an alternative concept, backed by three objections against Mill's project:<ref>Henry R. Searle: [https://archive.org/details/washingtonmonume00sear/page/n3/mode/2up ''Washington Monument – Monograph.''], Gibson Brothers Washington, D.C. 1847, page 3, in: [[Internet Archives]], retrieved February 11, 2024.</ref>
{{blockquote|First, would the foundation sustain the weight of the required height, and especially with the increased localized pressure in a storm of wind; second, the mere obelisk appeared only as an enlarged plagiarism, in no way illustrating the memory of Washington personally, or those connected with him, or the history of this growing country; third, there is nothing whatever aesthetic about it, and nothing that would impress the visitor, whether native or foreign, with the grandeur of the work of Washington and his coadjutors in founding this nation.}}
[[File:George_Washington_Statue_Inside_Washington_Monument.JPG|left|thumb|Bronze statue of [[George Washington]] in the monument's western alcove]]
Moreover, the estimated price tag of more than $1&nbsp;million ({{Inflation|US-GDP|1000000|1848|r=-7|fmt=eq}}) caused the society to hesitate. On April 11, 1848, the society decided, due to a lack of funds, to build only a simple plain obelisk. Mills's 1848 obelisk was to be {{convert|500|ft|m}} tall, {{convert|55|ft|m}} square at the base and {{convert|35|ft|m}} square at the top. It had two massive doorways, each {{convert|15|ft|m}} high and {{convert|6|ft|m}} wide, on the east and west sides of its base.<ref name="Torres" />{{rp|15, 21}} Surrounding each doorway were raised jambs, a heavy pediment, and entablature within which was carved an Egyptian-style [[winged sun]] and asps.<ref>Richard G. Carrott, ''The Egyptian Revival'', 1978, plate 33</ref><ref name="Torres">Louis Torres, [https://www.publications.usace.army.mil/Portals/76/Publications/EngineerPamphlets/EP_870-1-21.pdf ''"To the immortal name and memory of George Washington": The United States Army Corps of Engineers and the Construction of the Washington Monument''], (Washington, D.C.: US Government Printing Office, 1984).</ref>{{rp|23}}<ref name="Harvey" />{{rp|353+}} This original design conformed to a massive temple which was to have surrounded the base of the obelisk, but because it was never built, the architect of the second phase of construction [[Thomas Lincoln Casey Sr.|Thomas Lincoln Casey]] smoothed down the projecting jambs, pediment and entablature in 1885, walled up the west entrance with marble forming an alcove, and reduced the east entrance to {{convert|8|ft|m}} high.<ref name="Casey1885">[Thomas Lincoln Casey], [http://infoweb.newsbank.com/iw-search/we/Digital/?p_product=SERIAL&p_theme=sset2&p_nbid=U64Q5BHYMTQyMzY5Njg4NS44MDg5ODg6MToxNToxMzIuMTcwLjIwOC4yMjQ&p_action=doc&p_docnum=1&p_queryname=3&p_docref=v2:0FD2A62D41CEB699@SERIAL-10F552FC5400ED08@-@0 ''Letter from the Joint Commission for Completion of the Washington Monument, transmitting their annual report. December 15, 1885'']{{cbignore}} Congressional Serial Set, volume 2333, 49th Congress, 1st session, Senate Doc. 6. Available for free in most large United States libraries in government documents or online. Establish a connection to [http://www.readex.com/log-through-your-library ''Readex'' collections] before clicking on link.</ref><ref name="Torres" />{{rp|90{{ndash}}91}} A statue of Washington was eventually placed in the alcove in 1994.<ref name="Gordon q142">{{cite book |last=Gordon |first=John Steele |url=https://www.google.com/books/edition/Washington_s_Monument/A5EyEAAAQBAJ?hl=en&gbpv=1&dq=Bronze+statue+of+George+Washington+in+the+washington+monument&pg=PA6&printsec=frontcover |title=Washington's Monument: And the Fascinating History of the Obelisk |date=February 2, 2016 |publisher=Bloomsbury Publishing USA |isbn=978-1-62040-650-2}}</ref>{{Rp|page=6}}

===Construction===
[[File:Jefferson Pier and Washington Monument.jpg|thumb|The west side of [[Jefferson Pier]] with the Washington Monument (in background)|left]]
The Washington Monument was originally intended to be located at the intersection of a north–south axis through the center of the [[White House]], and a west–east axis through the [[United States Capitol|U.S. Capitol]] on [[Capitol Hill]]. This site had been allocated as part of the 1791 [[L'Enfant Plan]] for Washington, D.C.<ref name="L'Enfant Plan">Peter Charles L'Enfant's [http://hdl.loc.gov/loc.gmd/g3850.ct000512 "Plan of the city intended for the permanent seat of the government of t(he) United States&nbsp;..."] ''in'' [https://www.loc.gov/ official website of the U.S. Library of Congress]. Retrieved October 22, 2009. [[Freedom Plaza]] in downtown Washington, D.C., contains an inlay of the central portion of [[L'Enfant Plan|L'Enfant's plan]] and of its legends. {{webarchive |url=https://web.archive.org/web/20070730155115/http://www.loc.gov// |date=July 30, 2007 }}</ref>{{efn-ua | name=L'Enfant | L'Enfant identified himself as "Peter Charles L'Enfant" during most of his life, while residing in the United States. He wrote this name on his "Plan of the city intended for the permanent seat of the government of t(he) United States&nbsp;..." and on other legal documents.<ref name="L'Enfant Plan" /> However, during the early 1900s, the then French ambassador to the U.S., [[Jean Jules Jusserand]], popularized the use of L'Enfant's birth name, "Pierre Charles L'Enfant".<ref>Bowling, Kenneth R (2002). ''Peter Charles L'Enfant: vision, honor, and male friendship in the early American Republic.'' George Washington University, Washington, D.C.</ref>

The [[National Park Service]] identifies L'Enfant as "Major Peter Charles L'Enfant" and as "Major Pierre (Peter) Charles L'Enfant" on pages of its website that describe the Washington Monument.<ref>[https://web.archive.org/web/20070629094749/http://www.nps.gov/history/nr/travel/wash/text.htm#washington "Washington Monument" section ''in'' "Washington, D.C.: A National Register of Historic Places Travel Itinerary" page] ''in'' [https://www.nps.gov/index.htm official website of U.S. National Park Service]. Retrieved October 22, 2009.</ref><ref>[https://web.archive.org/web/20090430111423/http://www.nps.gov/nr/travel/presidents/washington_monument.html "Washington Monument" page ''in'' "American Presidents" section] ''of'' [https://www.nps.gov/index.htm official website of U.S. National Park Service]. Retrieved October 22, 2009.</ref> The [[United States Code]] states in {{UnitedStatesCode|40|3309}}: "(a) In General. – The purposes of this chapter shall be carried out in the District of Columbia as nearly as may be practicable in harmony with the plan of Peter Charles L'Enfant."
}}<!-- End of efn-ua --> The ground at the intended location proved to be too unstable to support such a heavy structure, so the monument's location was moved {{convert|390|ft|m|1}} east-southeast.{{efn-ua |The monument is located {{convert|370|ft|m|2}} east of the north–south White House axis, {{convert|123|ft|m|2}} south of the east–west Capitol axis, and {{convert|7387.4|ft|m|2}} west of the north–south Capitol axis.<ref name=Torres />{{rp|16}}<ref>[https://www.loc.gov/resource/mtj3.058_0468_0474/ Letter from Nicholas King, Surveyor of the City to Thomas Jefferson, October 15, 1804] Survey of Jefferson Pier. 7696.8 feet – 370 feet + 60.6 feet = 7387.4 feet.</ref>}} At that originally intended site there now stands a small monolith called the [[Jefferson Pier]].<ref>{{cite web|url=http://www.ngs.noaa.gov/cgi-bin/ds2.prl?retrieval_type=by_pid&PID=UA0024|title=Data Sheet Retrieval|work=noaa.gov}}</ref><ref>{{cite web|url={{NRHP url|id=66000035}}|page=Continuation Sheet, Item No. 7, p. 4|title=Jefferson Pier Marker|work=National Register of Historic Places Inventory – Nomination Form: Washington Monument|publisher=[[United States Department of the Interior]]: [[National Park Service]]|last=Pfanz|first=Donald C. |department=National Capital Region|date=December 2, 1980|access-date=February 13, 2012}}</ref> Consequently, the [[McMillan Plan]] specified that the [[Lincoln Memorial]] should be "placed on the main axis of the Capitol and the Monument", about 1° south of due west of the Capitol or the monument, not due west of the Capitol or the monument.<ref name=McMillan>{{cite book |editor-last=Moore |editor-first=Charles |title=The Improvement of the Park System of the District of Columbia |publisher=U.S. Government Printing Office |url=https://archive.org/details/bub_gb_Ob7PAAAAMAAJ |pages=[https://archive.org/details/bub_gb_Ob7PAAAAMAAJ/page/n99 51]–52 |date=1902}}</ref>{{efn-ua |The park portion of the [[National Mall|Mall]], including Madison Drive, Jefferson Drive, and four wide gravel boulevards between them east of the monument, and the [[Lincoln Memorial Reflecting Pool|Reflecting Pool]] and sidewalks west of the monument, are parallel to the offset Capitol-Monument-Lincoln axis. But the major highways immediately north and south of the Mall, [[Constitution Avenue]] and [[Independence Avenue (Washington, D.C.)|Independence Avenue]], are oriented east–west. This misalignment can be seen on a map of the area.}}

====Excavation and initial construction====
The [[cornerstone]] was laid with great ceremony on July 4, 1848.  The ceremony began with a parade of dignitaries in carriages, marching troops, fire companies, and benevolent societies.<ref name="Olszewski" />{{rp|chp 2}}<ref name="Harvey" />{{rp|44–48}}<ref name="DedicationCongress" />{{rp|16–17, 45–47}}  A long oration was delivered by [[Robert C. Winthrop]], the [[Speaker of the United States House of Representatives|speaker of the House of Representatives]].<ref name="Harvey" />{{rp|113–130}}  Subsequently, workers excavated the site, laid the cornerstone on the prepared bed, and laid the original foundation around and on top of the cornerstone. Construction of its massive walls began in 1849. Regarding modern claims of slave labor being used in construction, Washington Monument historian John Steele Gordon stated "I can't say for certain, but the stonemasonry was pretty highly skilled, so it's unlikely that slaves would've been doing it. The stones were cut by stonecutters, which is highly skilled work; and the stones were hoisted by means of steam engines, so you'd need a skilled engineer and foreman for stuff like that. Tending the steam engine, building the cast-iron staircase inside—that wasn't grunt work. ... The early quarries were in Maryland, so slave labor was undoubtedly used to quarry and haul the stone".<ref name=Riesman>{{cite web |last=Riesman |first=Abraham |url=http://www.vulture.com/2017/07/was-the-washington-monument-built-by-slaves.html |title=So, Was the Washington Monument Built by Slaves |date=July 10, 2017 |work=Slate |access-date=October 31, 2017}}</ref> Abraham Riesman, who quoted Gordon, states "there were plenty of people who worked as skilled laborers while enslaved in antebellum America. Indeed, there were enslaved people who worked as stonemasons. So the possibility remains that there were slaves who performed some of the necessary skilled labor for the monument."<ref name=Riesman /> According to historian Jesse Holland, it is very likely that African American slaves were among the construction workers, given that slavery prevailed in Washington and its surrounding states at that time, and slaves were commonly used in public and private construction.<ref>{{cite news|last1=Jesus|first1=Austin Elias-de|title=Spider-Man: Homecoming Says the Washington Monument Was Built by Slaves. Was It?|url=http://www.slate.com/blogs/browbeat/2017/07/11/was_the_washington_monument_built_by_slaves_spider_man_homecoming_says_yes.html|access-date=July 11, 2017|work=Slate|date=July 11, 2017}}</ref>

During the second phase, it is unlikely that slave labor was used, as every stone laid required dressing and polishing by a skilled stonemason. This includes the iron staircase which was constructed 1885–86. That the stonecutters in the quarry were slaves is confirmed because all quarry workers were slaves during the construction of the [[United States Capitol]] during the 1790s.<ref name=slaves>{{citation |last=Allen |first=William C. |title=History of Slave Laborers in the Construction of the United States Capital |url=https://emancipation.dc.gov/publication/history-slave-laborers-construction-us-capitol |date=June 1, 2005 |publisher=Office of the Architect of the Capitol}}</ref>{{rp|5–6}} However, most of the first phase's construction only required unskilled manual labor. No information survives concerning the method used to lift stones that weighed several tons each during the first phase, whether by a manual winch or a steam engine.<ref name=Torres />{{rp|17–23}} The surviving information concerning slaves that built the core of the United States Capitol during the 1790s is not much help. At the time, the [[District of Columbia (until 1871)|District of Columbia]] outside of [[Georgetown (Washington, D.C.)|Georgetown]] was sparsely populated so the federal government rented slaves from their owners who were paid a fee for their slaves' normal daily labor. Any overtime for Sundays, holidays, and nights was paid directly to the slaves which they could use for daily needs or to save to buy their freedom.<ref name=slaves />{{rp|9}} Conversely, the first phase of the monument was constructed by a private entity, the Washington National Monument Society.<ref name="Burns y782">{{cite book | last=Burns | first=John A. | title=Recording Historic Structures | publisher=John Wiley & Sons | date=December 1, 2003 | isbn=978-0-471-27380-6 | url=https://www.google.com/books/edition/Recording_Historic_Structures/FJUxS_yVomIC | page=51}}</ref>

Only a small number of stones used in the first phase required a skilled stonemason. These were the marble blocks on the outer surface of the monument (their inner surfaces were left very rough) and those gneiss stones that form the rough inner walls of the monument (all other surfaces of those inner stones within the walls were left jagged). The vast majority of all gneiss stones laid during the first phase, those between the outer and inner surfaces of the walls, from very large to very small jagged stones, form a pile of [[rubble]] held together by a large amount of [[mortar (masonry)|mortar]]. The [[#Foundation|original foundation]] below the walls was made of layered gneiss rubble, but without the massive stones used within the walls. Most of the gneiss stones used during the first phase were obtained from quarries in the upper [[Potomac River]] Valley. Almost all the marble stones of the first and second phases was [[Cockeysville Marble]], obtained from quarries north of downtown Baltimore in rural [[Baltimore County]] where stone for their first Washington Monument was obtained.<ref name="Loudermilk 1998 k599">{{cite web | last=Loudermilk | first=Suzanne | title=A monumental encore Quarries: Baltimore County marble was used in building the Washington Monument in the nation's capital, and marble from the same place might be used as it is restored. | website=Baltimore Sun | date=November 3, 1998 | url=https://www.baltimoresun.com/news/bs-xpm-1998-11-03-1998307058-story.html | access-date=June 29, 2023}}</ref>

On [[Independence Day (United States)|Independence Day]], July 4, 1848, the [[Freemasonry|Freemasons]], the same organization to which Washington belonged, laid the cornerstone (symbolically, not physically).<ref name=Harvey />{{rp|45, 136–143}} According to [[Joseph R. Chandler]]:<ref name=Harvey />{{rp|136, 140–141}}<ref name="Reading 2: Construction of the Monument" />

{{Blockquote|No more Washingtons shall come in our time ... But his virtues are stamped on the heart of mankind. He who is great in the battlefield looks upward to the generalship of Washington. He who grows wise in counsel feels that he is imitating Washington. He who can resign power against the wishes of a people, has in his eye the bright example of Washington.<ref name="Reading 2: Construction of the Monument">{{cite web | url=http://www.nps.gov/nr/twhp/wwwlps/lessons/62wash/62facts3.htm | archive-url=https://web.archive.org/web/20070831195843/http://www.nps.gov/nr/twhp/wwwlps/lessons/62wash/62facts3.htm | url-status=dead | archive-date=August 31, 2007 | title=Reading 2: Construction of the Monument | work=National Park Service | access-date=10 March 2015}}</ref>}}

Two years later, on July 4, 1850, [[George Washington Parke Custis]], the adopted son of George Washington, dedicated a stone from the people of the [[District of Columbia]] to the Monument at a ceremony.<ref>{{cite book|last=Perry|first=John|url=https://books.google.com/books?id=H4ig_dTZbzkC&pg=PA93|title=Lee: A Life of Virtue|publisher=Thomas Nelson|location=[[Nashville, Tennessee]]|year=2010|pages=93–94|isbn=978-1-59555-028-6|oclc=456177249}} At [[Google Books]].</ref>

====Donations run out====
[[File:Washington Monument circa 1860 - Brady-Handy.jpg|thumb|upright=1|The partially completed monument, photographed by [[Mathew Brady]], {{c.|1860}}]]
Construction continued until 1854, when donations ran out and the monument had reached a height of {{convert|152|ft|m|1}}. At that time a memorial stone that was contributed by [[Pope Pius IX]], called the Pope's Stone, was destroyed by members of the [[anti-Catholic]], [[nativism (politics)|nativist]] American Party, better known as the "[[Know-Nothings]]", during the early morning hours of {{nowrap|March 6, 1854}} (a priest replaced it in 1982 using the Latin phrase "A Roma Americae" instead of the original stone's English phrase "Rome to America"). Economic and political conditions of the time caused public contributions to the Washington National Monument Society to cease, so they appealed to Congress for money.<ref name=Torres />{{rp|23, 25–26}}<ref name=Jacob />{{rp|16, 215, 222–223}}

The request had just reached the floor of the [[United States House of Representatives|House of Representatives]] when the Know-Nothing Party seized control of the society on February 22, 1855, a year after construction funds ran out. Congress immediately tabled its expected contribution of $200,000 to the society, effectively halting the Federal appropriation. During its tenure, the Know-Nothing Society added only two courses of masonry, or {{convert|4|ft|m}}, to the monument using rejected masonry it found on site, increasing the height of the shaft to {{convert|156|ft|m}}. The original society refused to recognize the takeover, so the two rival societies existed side by side until 1858. With the Know-Nothing Party disintegrating and unable to secure contributions for the monument, it surrendered its possession of the monument to the original society three and a half years later on {{nowrap|October 20, 1858}}. To prevent future takeovers, the U.S. Congress incorporated the society on {{nowrap|February 22, 1859}}, with a stated charter and set of rules and procedures.<ref name=Olszewski />{{rp|chp 3}}<ref name=Harvey />{{rp|52–65}}

====Post–Civil War====

The [[American Civil War]] (1861–1865) halted all work on the monument, but interest grew after the war's end. Engineers studied the foundation several times to determine if it was strong enough for continued construction after 20 years of effective inactivity. In 1876, the [[United States Centennial|American Centennial]] of the [[United States Declaration of Independence|Declaration of Independence]], Congress agreed to appropriate another $200,000 to resume construction.<ref name="reeves413">{{cite book| last = Reeves| first = Thomas C.| title = Gentleman Boss| url = https://archive.org/details/gentlemanbosslif00reev| url-access = registration| date = February 1975| publisher = Alfred A. Knopf| location = New York| isbn = 978-0-394-46095-6| page = [https://archive.org/details/gentlemanbosslif00reev/page/413 413] }}</ref>
[[File:Washington Monument, 6 design proposals for the completion ca. 1879.jpg|thumb|Proposals for the completion of the monument published in 1879. Number 6, Henry R. Searle's obelisk was already made public in 1847.]]
Before work could begin again, arguments about the most appropriate design resumed. Many people thought a simple obelisk, one without the colonnade, would be too bare. Architect Mills was reputed to have said omitting the colonnade would make the monument look like "a stalk of [[asparagus]]"; another critic said it offered "little&nbsp;... to be proud of".<ref name="wash" />

This attitude led people to submit alternative designs. Both the Washington National Monument Society and Congress held discussions about how the monument should be finished. The society considered five new designs and an anonymous "interesting project of California" (which later turned out to be by [[Arthur Frank Mathews]]),<ref>Henry van Brunt: [https://archive.org/details/americanartamer01mont/page/n7/mode/1up?view=theater ''The Washington Monument.''], [[Internet Archives]], "American Art and Art Collections", Walter Montgomery (Editor), E. W. Walker and Company, Boston 1889, pages 354–368.</ref> concluding that the one by [[William Wetmore Story]], seemed "vastly superior in artistic taste and beauty". Congress deliberated over those five proposals (among others by Paul Schulze and [[John Fraser (architect)|John Fraser]]) as well as Mills's original. While it was deciding, it ordered work on the obelisk to continue. Finally, the members of the society agreed to abandon the colonnade and alter the obelisk so it conformed to classical Egyptian proportions.<ref name=nps3 />

====Resumption====
[[File:Washington Monument - Setting the capstone - Harper's Weekly.png|thumb|upright=1|P. H. McLaughlin setting the aluminum apex with Thomas Lincoln Casey (hands up)|left]]
Construction resumed in 1879 under the direction of Lieutenant Colonel [[Thomas Lincoln Casey Sr.|Thomas Lincoln Casey]] of the [[United States Army Corps of Engineers]]. Casey redesigned the foundation, strengthening it so it could support a structure that ultimately weighed more than 40,000 tons ({{convert|40,000|ST|t|disp=out|abbr=off}}). The first stone atop the unfinished stump was laid on August 7, 1880, in a small ceremony attended by President [[Rutherford B. Hayes]], Casey and a few others.<ref name="Torres" />{{rp|76}} Casey found 92 memorial stones ("presented stones") already inlaid into the interior walls of the first phase of construction. Before construction continued he temporarily removed eight stones at the {{convert|150|foot|m|adj=on}} level so that the walls at that level could be sloped outward, producing thinner second-phase walls. He inserted those stones and most of the remaining memorial stones stored in the lapidarium into the interior walls during 1885–1889.<ref name="Jacob" />{{rp|11–17}} The bottom third of the monument is a slightly lighter shade than the rest of the construction because the marble was obtained from different quarries.<ref>{{cite web | url=http://www.nps.gov/nr/travel/wash/dc72.htm | archive-url=https://web.archive.org/web/20070913113505/http://www.nps.gov/nr/travel/wash/dc72.htm | url-status=dead | archive-date=September 13, 2007 | title=Washington Monument | work=National Park Service | access-date=March 10, 2015 | quote=The walls of the monument range in thickness from 15' at the base to 18' at the upper shaft. They are composed primarily of white marble blocks from Maryland with a few from Massachusetts, underlain by Maryland blue gneiss and Maine granite. A slight color change is perceptible at the 150' level near where construction slowed in 1854.}}</ref>

The building of the monument proceeded quickly after Congress had provided sufficient funding. In four years, it was completed, with the 100-ounce (2.83&nbsp;kg) aluminum apex/lightning-rod being put in place on December 6, 1884.<ref name="reeves413" /> The apex was the largest single piece of aluminum cast at the time, when aluminum commanded a price comparable to silver.<ref name="Binczewski">{{cite journal|author = George J. Binczewski|title = The Point of a Monument: A History of the Aluminum Cap of the Washington Monument|journal = JOM|volume = 47|issue = 11|pages = 20–25|year = 1995|url = http://www.tms.org/pubs/journals/JOM/9511/Binczewski-9511.html|doi=10.1007/bf03221302|bibcode = 1995JOM....47k..20B|s2cid = 111724924|url-access = subscription}}</ref> Two years later, the [[Hall–Héroult process]] made aluminum easier to produce and the price of aluminum plummeted, though it should have provided a lustrous, non-rusting apex.{{efn-ua |name=rust |The large gold-plated copper band added to the aluminum apex in 1885 discolored or damaged the surface of the aluminum so much that most of its inscriptions are no longer legible – see [[#Aluminum apex|Aluminum apex]].}}<ref>{{cite web |url = http://portal.acs.org/portal/PublicWebSite/education/whatischemistry/landmarks/aluminumprocess/index.htm |archive-url = https://archive.today/20130223151952/http://portal.acs.org/portal/PublicWebSite/education/whatischemistry/landmarks/aluminumprocess/index.htm |url-status = dead |archive-date = February 23, 2013 |title = Hall Process: Production and Commercialization of Aluminum |publisher = American Chemical Society |work = National Historic Chemical Landmarks |access-date = March 25, 2013 }}</ref> The monument opened to the public on October 9, 1888.<ref>[http://www.cr.nps.gov/nr/travel/wash/dc72.htm "Washington Monument"] {{webarchive |url=https://web.archive.org/web/20141227003638/http://www.cr.nps.gov/nr/travel/wash/dc72.htm |date=December 27, 2014 }}. ''Teaching with Historic Places''. National Park Service. Retrieved October 15, 2006.</ref>

===Dedication===
[[File:View of the uncompleted Washington Monument, taken from the roof of the Main building of the Department of... - NARA - 516531.jpg|thumb|upright=1|Washington Monument nears completion around 1884]]
The Monument was dedicated on February 21, 1885.<ref name="DedicationNYT">[https://timesmachine.nytimes.com/timesmachine/1885/02/22/103628255.pdf Marking a people's love], an article from [[The New York Times]] published February 22, 1885.</ref> Over 800 people were present on the monument grounds to hear speeches by Ohio senator [[John Sherman (politician)|John Sherman]], the Rev. Henderson Suter, [[William Wilson Corcoran]] of the Washington National Monument Society (read by James C. Welling), [[Freemason]] Myron M. Parker, Col. Thomas Lincoln Casey of the [[United States Army Corps of Engineers|Army Corps of Engineers]], and President [[Chester A. Arthur]].<ref name="reeves413" /><ref name="Harvey" />{{rp|104}}<ref name="Crutchfield">{{cite book|last=Crutchfield|first=James A.|url=https://books.google.com/books?id=VxP8vG5I2NkC&pg=PA218|page=218|title=George Washington: First in War, First in Peace|year=2005|location=New York|publisher=A Forge Book: Tom Doherty Associates, LLC|isbn=0-7653-1069-4|oclc=269434694}}</ref> President Arthur proclaimed:<blockquote> I do now&nbsp;... in behalf of the people, receive this monument&nbsp;... and declare it dedicated from this time forth to the immortal name and memory of George Washington.<ref name=Crutchfield /></blockquote>
[[File:Washington-Monument-1885.png|thumb|upright=1|Monument plans and timeline of construction]]
After the speeches, Lieutenant-General [[Philip Sheridan]] led a procession past the [[White House]], via [[Pennsylvania Avenue]] to the east main entrance of the [[United States Capitol|Capitol Building]], where U.S. representative [[John Davis Long]] read a speech written a few months earlier by [[Robert C. Winthrop]].<ref name=Harvey />{{rp|234–260}} A final speech was given by U.S. senator [[John W. Daniel]]. The festivities concluded that evening with fireworks, both aerial and ground displays.<ref name=Harvey />{{rp|260–285}}<ref name=DedicationCongress>[https://archive.org/details/dedicationofwash00unit ''The Dedication of the Washington National Monument''], 1885.</ref><ref name="reeves414">{{cite book| last = Reeves| first = Thomas C.| title = Gentleman Boss| url = https://archive.org/details/gentlemanbosslif00reev| url-access = registration| date = 1975| publisher = Alfred A. Knopf| location = New York| isbn = 978-0-394-46095-6| page = [https://archive.org/details/gentlemanbosslif00reev/page/414 414] }}</ref> The total cost of the monument from 1848 to 1888 was $1,409,500<ref name="Snell" /> ({{Inflation|US-GDP|1409500|1882|r=-7|fmt=eq}}).<ref>[http://liberalarts.oregonstate.edu/spp/polisci/faculty-staff/robert-sahr/inflation-conversion-factors-years-1774-estimated-2024-dollars-recent-years/download-conversion-factors Download Conversion Factors] {{webarchive|url=https://web.archive.org/web/20160829070746/http://liberalarts.oregonstate.edu/spp/polisci/faculty-staff/robert-sahr/inflation-conversion-factors-years-1774-estimated-2024-dollars-recent-years/download-conversion-factors|date=August 29, 2016}} Oregon State University.</ref> 

===Later history===
[[File:White House from the Washington Monument, Washington, D.C..jpg|thumb|upright=1|View of the [[White House]] and Northern Washington from the top of the Washington Monument in the early 1900s]]
The Washington Monument was the world's tallest structure until the [[Eiffel Tower]] in [[Paris]] was completed in 1889.<ref>{{cite web|url=http://www.emporis.com/en/wm/bu/?id=washingtonmonument-washington-dc-usa|archive-url=https://web.archive.org/web/20070309215757/http://www.emporis.com/en/wm/bu/?id=washingtonmonument-washington-dc-usa|url-status=usurped|archive-date=March 9, 2007|title=Washington Monument|publisher=Emporis.com|access-date=July 6, 2008}}</ref><ref name="Curlee e092">{{cite book |last=Curlee |first=Lynn |url=https://www.google.com/books/edition/Skyscraper/oPFiEQAAQBAJ |title=Skyscraper |date=2025 |publisher=Simon and Schuster |isbn=978-1-6659-6907-9 |page=3}}</ref> This monument is taller than the obelisks around the capitals of Europe and in [[Egypt]] and [[Ethiopia]], but ordinary antique obelisks were quarried as a monolithic block of stone, and were therefore seldom taller than approximately {{convert|100|ft|m}}.<ref>[[Edward Chaney]], "Roma Britannica and the Cultural Memory of Egypt: Lord Arundel and the Obelisk of Domitian", in ''Roma Britannica: Art Patronage and Cultural Exchange in Eighteenth-Century Rome'', eds. D. Marshall, K. Wolfe and S. Russell, British School at Rome, 2011, pp. 147–170.</ref> The district's [[Heights of Buildings Act of 1910]] restricts new building heights to no more than {{convert|20|ft|m}} greater than the width of the adjacent street; as such, none of [[List of tallest buildings in Washington, D.C.|Washington, D.C.'s tallest buildings]] are higher than the Washington Monument.<ref name="Brookings m282">{{cite web |date=August 15, 2024 |title=Up or out: How the Height Act hinders development in Washington, DC |url=https://www.brookings.edu/articles/up-or-out-how-the-height-act-hinders-development-in-washington-dc/ |access-date=November 8, 2025 |website=Brookings}}</ref>

==== 20th century ====
In the early 1900s, material started oozing out between the outer stones of the first construction period below the {{convert|150|foot|m|adj=on}} mark, and was referred to by tourists as "geological tuberculosis". This was caused by the weathering of the cement and rubble filler between the outer and inner walls. As the lower section of the monument was exposed to cold and hot and damp and dry weather conditions, the material dissolved and worked its way through the cracks between the stones of the outer wall, solidifying as it dripped down their outer surface.<ref>[https://books.google.com/books?id=-t0DAAAAMBAJ&pg=PA829 "Washington Monument attacked by Geological Tuberculosis"]  {{webarchive|url=https://web.archive.org/web/20160902190729/https://books.google.com/books?id=-t0DAAAAMBAJ&pg=PA829 |date=September 2, 2016 }} ''Popular Mechanics'', December 1911, pp. 829–830. This source mistakenly said the lower 190 feet was constructed during the early period—it was actually 150 feet.</ref>

For ten hours in December 1982, the Washington Monument and eight tourists were held hostage by a nuclear arms protester, [[Norman Mayer]], claiming to have explosives in a van he drove to the monument's base. [[United States Park Police]] shot and killed Mayer. The monument was undamaged in the incident, and it was discovered later that Mayer did not have explosives. After this incident, the surrounding grounds were modified in places to restrict the possible unauthorized approach of motor vehicles.<ref>{{cite book|author=Jeffrey David Simon|title=The Terrorist Trap: America's Experience with Terrorism|url=https://archive.org/details/terroristtrapame00simo|url-access=registration|year=2001|publisher=Indiana UP|page=[https://archive.org/details/terroristtrapame00simo/page/285 285]}}</ref>

==== 1990s and 2000s renovations ====
[[File:WashingtonMonumentSenorAnderson.jpg|left|thumb|upright=1|The monument undergoing restoration in 1999]]The monument underwent an extensive restoration project between 1998 and 2001. During this time it was completely covered in scaffolding designed by [[Michael Graves]] (who was also responsible for the interior changes).<ref>{{cite news |title=Obelisk's Scaffold Is First of Its Kind |author=Gabriel Escobar |url=https://www.washingtonpost.com/wp-srv/local/longterm/library/monument/monument.htm |newspaper=Washington Post |date=December 30, 1998 |access-date=June 13, 2011}}</ref> The project included cleaning, repairing and [[repointing]] the monument's exterior and interior stonework; adding glass encasements around stone in publicly accessible interior spaces to prevent vandalism; and adding windows with narrower frames to increase the viewing space. New exhibits celebrating the life of George Washington, and the monument's place in history, were also added.<ref name="reopening_Washington_Post">{{cite news |title=It's Ready for Its Close-Up Now: Big Crowds Are Expected For Monument's Reopening |author=Linda Wheeler |newspaper=The Washington Post |date=July 30, 2000}}</ref>

A temporary interactive visitor center, dubbed the "Discovery Channel Center", was also constructed during the project. The center provided a simulated ride to the top of the monument, and shared information with visitors during phases in which the monument was closed.<ref>{{cite news |title=Metro in Brief |newspaper=The Washington Post |date=August 30, 2000}}</ref> The majority of the project's phases were completed by summer 2000, allowing the monument to reopen July 31, 2000.<ref name="reopening_Washington_Post" /> The monument temporarily closed again on December 4, 2000, to allow a new elevator cab to be installed, completing the final phase of the restoration project. The new cab included glass windows, allowing visitors to see some of the 194 memorial stones with their inscriptions embedded in the monument's walls. The installation of the cab took much longer than anticipated, and the monument did not reopen until February 22, 2002. The final cost of the restoration project was $10.5&nbsp;million.<ref>{{cite news |title=New sight from Washington Monument |author=John Heilprin |url=http://www.deseretnews.com/article/897639/New-sight-from-Washington-Monument.html |archive-url=https://web.archive.org/web/20120120071431/http://www.deseretnews.com/article/897639/New-sight-from-Washington-Monument.html |url-status=dead |archive-date=January 20, 2012 |newspaper=Deseret News |date=February 23, 2002 |access-date=June 13, 2011}}</ref>

On September 7, 2004, the monument closed for a $15&nbsp;million renovation, which included numerous security upgrades and redesign of the monument grounds by landscape architect [[Laurie Olin]] (b. 1938). The renovations were due partly to security concerns following the [[September 11 attacks|September 11, 2001 attacks]] and the start of the [[war on terror]]. The monument reopened April 1, 2005, while the surrounding grounds remained closed until the landscape was finished later that summer.<ref>{{cite news |title=Washington Monument reopens to public |url=https://www.usatoday.com/news/washington/2005-04-01-wash-monument-reopens_x.htm |newspaper=USA Today |date=April 1, 2005 |access-date=June 9, 2011}}{{dead link|date=December 2024}}</ref><ref>{{cite news |title=Washington Monument To Reopen Next Month |author=Paul Schwartzman |url=https://www.washingtonpost.com/wp-dyn/articles/A48152-2005Mar18.html |newspaper=The Washington Post |date=March 19, 2005 |access-date=June 9, 2011}}</ref>

====2010s to present====
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[[File:Washington Monument 2024.jpg|The monument in March 2024|thumb]]
On August 23, 2011, the Washington Monument sustained damage during the 5.8 magnitude [[2011 Virginia earthquake]].<ref>{{cite news |title=Disasters Washington Monument Indefinitely Closes After Earthquake Causes Cracks |author=FoxNews.com |url=https://www.foxnews.com/us/washington-monument-indefinitely-closes-after-earthquake-causes-cracks |date=August 23, 2011 |access-date=August 23, 2011 |work=Fox News}}</ref> Over 150 cracks were found in the monument,<ref name="cnn 20140512" /> which was closed indefinitely after a crack was found at the pinnacle.<ref name="QuakeAP">{{cite news|title=Washington Monument top cracked by earthquake |agency=Associated Press |url=https://www.google.com/hostednews/ap/article/ALeqM5jecxYo23gZVajPXprpTBjDSpSZlw?docId=9def79ebf5fb4459b6e61832f006bc98 |access-date=August 24, 2011 }}{{dead link|date=June 2024|bot=medic}}{{cbignore|bot=medic}}</ref><ref name="RuaneMoreDamage">{{cite news|author=Michael E. Ruane |url=https://www.washingtonpost.com/local/washington-monuments-elevator-damaged-in-earthquake/2011/09/26/gIQA55wazK_story.html |title=Washington Monument Elevator Damage Inspected as Earthquake's Toll Is Assessed |newspaper=Washington Post |date=September 26, 2011 |access-date=January 31, 2013}}</ref> Other pieces of the monument became dislodged.<ref name="SullivanBlock">[https://www.washingtonpost.com/blogs/post_now/post/washington-monument-cracks-indicate-earthquake-damage-photos/2011/08/25/gIQAfFwmdJ_blog.html Sullivan, Patricia. "Washington Monument Cracks Indicate Earthquake Damage." ''Washington Post.'' August 25, 2011.] Assessed August 26, 2011.</ref> Two structural engineering firms—[[Wiss, Janney, Elstner Associates, Inc.]] and Tipping Mar Associates—were hired to assess the monument.<ref>[https://www.nps.gov/nama/learn/news/washington-monument-finds-additional-cracks.htm "Washington Monument Finds Additional Cracks." Press release. National Park Service. U.S. Department of the Interior. August 25, 2011] . Retrieved August 26, 2011.</ref> An examination of the monument's exterior revealed debris had become dislodged around and inside the memorial.<ref name="RuaneMoreDamage" /> The elevator system had been damaged operating only to the {{convert|250|ft|m|adj=on}} level, but was soon repaired.<ref>{{cite web |url=http://blogs.govexec.com/fedblog/2011/09/washington_monument_elevator_w.php |author=Clark, Charles S. |title=Washington Monument Elevator Woes |publisher=Government Executive |date=August 21, 2012 |access-date=January 31, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120117192356/http://blogs.govexec.com/fedblog/2011/09/washington_monument_elevator_w.php |archive-date=January 17, 2012  }}</ref> A group of climbers conducted further investigations that September because the NPS suspected that there were more cracks on the monument's upper section that were not visible from the inside.<ref name="RuaneMoreDamage" /><ref name="ReutersDamage">{{cite news|last=O'Toole |first=Molly |url=https://www.reuters.com/article/us-washington-monument-idUSTRE78P5RA20110926 |title=Engineers to Rappel Down Washington Monument to Inspect Damage|date=September 26, 2011 |agency=Reuters.com |access-date=January 31, 2013}}</ref> The external inspection found cracks and [[spalling]] near the top of the monument, and more loss of joint mortar further down the monument. The full report was issued in December 2011.<ref name="Earthquake">{{cite web |url=http://www.nps.gov/wamo/upload/Post-Earthquake-assessment12_22_logo.pdf |archive-url=https://web.archive.org/web/20120227034618/http://www.nps.gov/wamo/upload/Post-Earthquake-assessment12_22_logo.pdf |url-status=dead |archive-date=February 27, 2012 |title=Post-Earthquake Assessment |website=www.nps.gov |publisher=National Park Service |date=December 22, 2011 |access-date=January 4, 2016}}</ref> More than $200,000 was spent between August 24 and September 26 inspecting the structure.<ref name="RuaneMoreDamage" />  Bob Vogel, Superintendent of the National Mall and Memorial Parks, emphasized that the monument was not in danger of collapse.<ref name="ReutersDamage" /> 

The NPS announced in 2012 that the monument would be closed for repairs until 2014,<ref>{{cite news|last=Cohn|first=Alicia|title=Washington Monument could be closed until 2014 for earthquake repairs|url=https://thehill.com/blogs/blog-briefing-room/news/119077-washington-monument-could-be-closed-until-2014-for-earthquake-repairs/|newspaper=The Hill|access-date=July 9, 2012}}</ref> hiring [[Hill International]] and [[Louis Berger Group]] to provide coordination between the designer, Wiss, Janney, and Elstner Associates, the general contractor [[Tutor Perini|Perini]], and numerous stakeholders.<ref name="CMAA 2014">{{cite web | title=Washington Monument Earthquake Repair | website=CMAA | date=May 1, 2014 | url=http://cmaanet.org/impact-library/washington-monument-earthquake-repair | access-date=July 15, 2015 | archive-url=https://web.archive.org/web/20150715223037/http://cmaanet.org/impact-library/washington-monument-earthquake-repair | archive-date=July 15, 2015 | url-status=dead | df=mdy-all }}</ref> NPS said a portion of the plaza at the base of the monument would be removed and [[scaffolding]] constructed around the exterior.<ref>{{cite web|last=Freed|first=Benjamin R.|title=Washington Monument Nearly Topped Out, Will Be Lighted in June|url=http://dcist.com/2013/05/washington_monument_scaffolding_nea.php#photo-1|access-date=May 9, 2013|url-status=live|archive-url=https://web.archive.org/web/20130506034946/http://dcist.com/2013/05/washington_monument_scaffolding_nea.php#photo-1|archive-date=May 6, 2013}}</ref> Some stone pieces saved during the 2011 inspection would be refastened to the monument, while "Dutchman patches"{{efn-ua |name=Dutchman | A "Dutchman Repair" "is a type of partial replacement or 'piecing-in'" that "involves replacing a small area of damaged stone" with a small piece of natural or imitation stone, "wedged in place or secured with an adhesive", with the joint being "as narrow as possible to maintain the appearance of a continuous surface".<ref>[https://www.nps.gov/tps/how-to-preserve/preservedocs/Historic-Masonry-Deterioration.pdf Grimmer, Anne E., "Dutchman Repair" (1984)],''A Glossary of Historic Masonry Deterioration Problems and Preservation Treatments''. Washington, D.C.: Department of the Interior, National Park Service Preservation Assistance Division. p. 56. Retrieved April 3, 2013.</ref> <!-- end of efn-ua -->}} would be used in other places. Several of the stone lips that help hold the pyramidion's exterior slabs in place were also damaged, so engineers installed stainless steel brackets to more securely fasten them to the monument.<ref>[https://www.washingtonpost.com/local/earthquake-damaged-washington-monument-may-be-closed-into-2014/2012/07/09/gJQAXrTNYW_story.html Ruane, Michael E. "Earthquake-Damaged Washington Monument May Be Closed Into 2014." ''Washington Post.'' July 9, 2012]. Retrieved July 14, 2012</ref> The National Park Service reopened the Washington Monument to visitors on May 12, 2014, eight days ahead of schedule.<ref name="reopening">{{cite web|url=https://www.nps.gov/wamo/washington-monument-reopening.htm|title=Washington Monument reopening|publisher=National Park Service|access-date=May 12, 2014}}</ref><ref name="CMAA 2014" /> Repairs to the monument cost $15&nbsp;million,<ref name="cnn 20140512">{{cite web|url=http://www.cnn.com/2014/05/12/travel/washington-monument-to-reopen/ |title=Washington Monument reopens after quake repairs |publisher=CNN.com |date=August 23, 2011 |access-date=May 14, 2014}}</ref> with taxpayers funding $7.5&nbsp;million of the cost and [[David Rubenstein]] funding the other $7.5&nbsp;million.<ref name="abc 20140512">{{cite web|url=https://abcnews.go.com/Politics/10-facts-washington-monument-reopens/story?id=23683473 |title=10 Facts About the Washington Monument as It Reopens |publisher=ABC News |access-date=May 14, 2014}}</ref> 

The monument continued to be plagued by problems after the earthquake, including in January 2017 when the lights illuminating it went out.<ref>[https://www.washingtonpost.com/news/local/wp/2017/01/04/lights-out-at-the-washington-monument/ "The lights went out at the Washington Monument"], Dana Hedgpeth. [[Washington Post]]. January 4, 2017. Retrieved January 4, 2017</ref> The monument was closed again in September 2016 due to reliability issues with the elevator system.<ref>{{cite news|url=https://www.washingtonpost.com/local/washington-monument-to-close-for-repairs-elevator-is-unreliable-officials-say/2016/09/26/350e2244-83f9-11e6-ac72-a29979381495_story.html |title=Washington Monument closed indefinitely over elevator's 'reliability issues' | first1 = Dana | last1 = Hedgpeth | first2 = Michael E. |last2 = Ruane |newspaper=[[The Washington Post]] | date = September 26, 2016 | access-date = September 26, 2016}}</ref> On December 2, 2016, the PS announced that the monument would be closed until 2019 in order to modernize the elevator. The $2–3&nbsp;million project was to correct the elevator's ongoing mechanical, electrical and computer issues, which had shuttered the monument since August 17. The NPS also requested funding for a permanent screening facility for the Washington Monument.<ref>{{Cite web|url=https://www.nps.gov/nama/learn/news/david-rubenstein-donates-funds-to-modernize-washington-monument-elevator.htm|archive-url=https://web.archive.org/web/20161203062325/https://www.nps.gov/nama/learn/news/david-rubenstein-donates-funds-to-modernize-washington-monument-elevator.htm|url-status=dead|archive-date=December 3, 2016|title=David Rubenstein Donates Funds to Modernize Washington Monument Elevator – National Mall and Memorial Parks (U.S. National Park Service)|website=www.nps.gov|access-date=December 2, 2016}}</ref> The final months of closure were for mitigation of possibly contaminated underground soil thought to have been introduced in the 1880s.<ref>{{cite news |url=https://thehill.com/policy/energy-environment/438930-washington-monument-reopening-delayed-by-possible-soil/ |title=Washington Monument reopening delayed by possible soil contamination |date=April 15, 2019 |newspaper=The Hill |first=Rebecca |last=Beitsch |access-date=July 15, 2019 }}</ref> The monument reopened September 19, 2019.<ref name="Lefrak j645">{{cite web |last=Lefrak |first=Mikaela |date=September 19, 2019 |title=Our Long 3-Year Wait Is Over: The Washington Monument Reopens |url=https://www.keranews.org/2019-09-19/our-long-3-year-wait-is-over-the-washington-monument-reopens |access-date=November 10, 2025 |website=KERA News}}</ref>

The Washington Monument was closed on March 14, 2020, because of the [[COVID-19 pandemic]].<ref>Jen Rose Smith. [https://www.cnn.com/travel/article/us-national-parks-closed-coronavirus-wellness/index.html "These US national parks are closed because of coronavirus."] CNN Travel, 17 March 2020. Retrieved 20 August 2021.</ref>  It reopened on October 1, 2020,<ref name="Lantry">Lauren Lantry. [https://abcnews.go.com/Politics/washington-monument-reopening-wednesday-closed-covid/story?id=78809903 "The Washington Monument is reopening Wednesday after being closed because of COVID."] ''ABC News.'' 14 July 2021.  Retrieved 20 August 2021.</ref> and remained open through the remainder of that year, except for brief closures.<ref>Joey Garrison. [https://www.usatoday.com/story/news/politics/2020/12/18/washington-monument-closed-down-after-secretary-positive-covid-19/3958784001/ "Washington Monument closed down after Interior Secretary tests positive for COVID-19."] ''USA Today.'' 18 December 2020. Retrieved 20 August 2021.</ref> On January 11, 2021, a few days after the [[January 6 United States Capitol attack]], the National Park Service announced a two-week closure until after the [[Inauguration of Joe Biden|presidential inauguration]];<ref>{{cite news |url=https://thehill.com/policy/energy-environment/533634-washington-monument-closed-through-inauguration-due-to-credible/ |title=Washington Monument closed through inauguration due to 'credible threats' |date=January 11, 2021 |work=The Hill |first=Rebecca |last=Beitsch |access-date=January 11, 2021 }}</ref> despite a lack of violence, the closure was extended due to a revival of COVID-19 fears.<ref>Greg Clary. [https://www.cnn.com/2021/01/23/politics/washington-monument-closed-coronavirus/index.html "."] ''CNN Politics''. 23 January 2021. Retrieved 20 August 2021.</ref> The monument then reopened on July 14, 2021,<ref name="Lantry" /> only to close yet again on August 16 for two weeks due to lightning strikes which damaged some electrical systems.<ref>Alejandro Alvarez. [https://wtop.com/local/2021/08/washington-monument-closed-for-4th-day-after-lightning-strike/ "Washington Monument closed for 4th day after lightning strike."] ''WTOP News.''. 19 August 2021. Retrieved 20 August 2021.</ref>

==Components==

===Foundation===
[[File:Washington Monument foundation.png|thumb|upright=1|Cross section of foundation, both old and reinforced, showing dimensions]]
The first phase began with the excavation of about {{convert|7|ft|8|in|m|1}} of topsoil down to a level of [[loam]], consisting of equal parts of sand and clay, hard enough to require [[pickaxe|picks]] to break it up. On this "bed of the foundation" the [[#Cornerstone|cornerstone]] was laid at the northeast corner of the proposed foundation. The rest of the foundation was then constructed of bluestone gneiss rubble and spalls, with every crevice filled with [[lime mortar]].<ref name="Torres" />{{rp|23, 68}} The dimensions of this old foundation were {{convert|23|ft|4|in|m|1}} high, {{convert|80|ft|m|1}} square at the base, and {{convert|58|ft|6|in|m|1}} square at the top, laid down in eight steps, similar to a truncated [[step pyramid]].<ref name="Torres" />{{rp|18–19, 23, 47}} At the center of the foundation a brick-lined {{convert|2|ft|cm|-1|adj=on}} square well was dug to a depth of {{convert|20|ft|m|0}} below the bed of the foundation to keep it dry and to supply water during construction.<ref name="Torres" />{{rp|19}}

During the second phase, after determining that the proposed weight of the monument was too great for the old foundation to safely bear, the thickness of the walls atop the unfinished stump was reduced and the foundation was strengthened by adding a large unreinforced concrete slab below the perimeter of the old foundation to increase the monument's load bearing area two and one half times. The slab was {{convert|13|ft|6|in|m|1}} thick, with an outer perimeter {{convert|126|ft|5+1/2|in|m|2}} square, an inner perimeter {{convert|44|ft|m|1}} square, with undisturbed loam inside the inner perimeter except for the water well. The area at the base of the second phase foundation is {{convert|15992|sqft|m2|1}}. The strengthened foundation (old foundation and concrete slab) has a total depth of {{convert|36|ft|10|in|1}} below the bottom of the lowest course of marble blocks (now below ground), and {{convert|38|ft|m|1}} below the entry lobby floor. Casey reported that nowhere did the load exceed {{convert|9|LT/sqft|psi kPa}} and did not exceed {{convert|3|LT/sqft|psi kPa}} near the outer perimeter.<ref name="Casey1884" /> To properly distribute the load from the shaft to slab, about half by volume of the outer periphery of the old rubble foundation below its top step was removed. A continuous sloping unreinforced concrete buttress encircles what remains. The buttress is {{convert|100|ft|4|in|m|1}} square at its base, {{convert|64|ft|6|in|m|1}} square at its top, and {{convert|20|ft|5|in|m|1}} high. The perimeter of the original top step of the old rubble foundation rests on the larger top of the concrete buttress. Its slope (lower external angle from the vertical) is 49°. This buttress rests in a depression (triangular cross-section) on the top surface of the concrete slab. The slab was constructed by digging pairs of {{convert|4|ft|m|1|adj=on}} wide [[drift mining|drifts]] on opposite sides of the monument's center line to keep the monument properly balanced. The drifts were filled with unreinforced concrete with depressions or dowel stones on their sides to interlock the sections.<ref name="HSR" />{{rp|3{{hyphen}}3{{ndash}}3{{hyphen}}5, figs 3.1{{ndash}}3.6, 3.9, 3.13, 4.11}}<ref name="Torres" />{{rp|39, 47{{ndash}}48, 67{{ndash}}73}} The weight of the foundation is {{convert|36912|LT|ST t|0|abbr=off}}.<ref name="Casey1884" />

===Cornerstone===
The [[cornerstone]] was laid at the northeast corner of the lowest course of the old [[#Foundation|foundation]] on {{nowrap|July 4, 1848}}.<ref name=Torres />{{rp|20}} Therefore, the cornerstone was laid below the 1848 ground level. In 1880, the ground level was raised {{convert|17|ft|m}}.<ref name=HSR />{{rp|B-36–B-39 <!-- page within chapter numbering --> }}<ref name=Torres />{{rp|70, 95–96}} If the cornerstone had not been moved during the strengthening of the foundation in 1879–80, its upper surface would now be {{convert|21|ft|m}} below the [[Pavers (flooring)|pavement]] just outside the northeast corner of the shaft. It would now be sandwiched between the concrete slab under the old foundation and the concrete buttress completely encircling what remains of the old foundation. During the strengthening process, about half by volume of the periphery of the lowest seven of eight courses or steps of the old foundation (gneiss rubble) was removed to provide good footing for the buttress. Although a few diagrams, pictures and descriptions of this process exist, the fate of the cornerstone is not mentioned.<ref name=HSR>John Milner Associates, [https://www.nps.gov/parkhistory/online_books/wamo/wash_hsr1.pdf ''Historic Structure Report: Washington Monument''] , 2004 (HSR)</ref>{{rp|2{{hyphen}}7{{ndash}}2{{hyphen}}8, 3{{hyphen}}3{{ndash}}3{{hyphen}}5, 4{{hyphen}}3{{ndash}}4{{hyphen}}4, B{{hyphen}}11{{ndash}}B{{hyphen}}18, <!-- page within chapter numbering --> figs 2.5{{ndash}}2.7, 3.2{{ndash}}3.6, 3.13, 4.8{{ndash}}4.11}}<ref name=Torres />{{rp|67–73}} <!-- The National Archives may mention its fate. Page B-17 of "Annotated Chronology" (Appendix B) of the ''Historic Structure Report'' notes that during 3/1880 excavation of the northeast corner of the old foundation occurred in preparation for the continuous buttress, referring to note 100 on page B-69 for the specific report (abbreviations on page B-63). Harvey 1903 between pages 353 and 354 has north and east views of the old foundation prior to its strengthening that do not show a smooth white squared cornerstone, only gneiss slabs, small or large, smooth on top and rough on their sides, on the outside of the lowest step of the old foundation, so the slabs were probably intentionally placed around and over the cornerstone in 1848. -->

The cornerstone was a {{convert|24,500|lb|kg|adj=on}} marble block {{convert|2.5|ft|m}} high and {{convert|6.5|ft|m}} square with a large hole for a zinc case filled with memorabilia. The hole was covered by a copper plate inscribed with the date of the [[United States Declaration of Independence|Declaration of Independence]] (July 4, 1776), the date the cornerstone was laid (July 4, 1848), and the names of the managers of the Washington National Monument Society. The memorabilia in the zinc case included items associated with the monument, the city of Washington, the national government, state governments, benevolent societies, and George Washington, plus miscellaneous publications, both governmental and commercial, a coin set, and a Bible, totaling 73 items or collections of items, as well as 71 newspapers containing articles relating to George Washington or the monument.<ref name=Olszewski />{{rp|app C}}<ref name=Harvey>Frederick L. Harvey, [https://books.google.com/books?id=6mVBAQAAMAAJ&pg=PA1 ''History of the Washington National Monument and Washington National Monument Society''], Congressional Serial Set, volume 4436, 57th Congress, 2nd session, Senate Doc. 224, 1903. The smaller 1902 edition has the slightly different name [https://archive.org/details/historywashingt00harvgoog ''History of the Washington National Monument and of the Washington National Monument Society'']. The 1903 edition is about three times the size of the 1902 edition principally due to its inclusion of the full texts of many documents and speeches.</ref>{{rp|pp 43–46, 109–166}}

===Memorial stones===
[[File:Washington Monument Deseret Stone in 2000.jpg|thumb|upright=1|alt=Photo of the Washington Monument Memorial Stone from Utah (State of Deseret)|Memorial stone from [[Utah]], representing the former provisional [[State of Deseret]]]]
States, cities, foreign countries, benevolent societies, other organizations, and individuals have contributed 194 memorial stones, all inserted into the east and west interior walls above stair landings or levels for easy viewing, except one on the south interior wall between stairs that is difficult to view. The sources disagree on the number of stones for two reasons: whether one or both "height stones" are included, and stones not yet on display at the time of a source's publication cannot be included. The "height stones" refer to two stones that indicate height: during the first phase of construction a stone with an inscription that includes the phrase "from the foundation to this height 100 feet" ({{convert|100|ft|m|disp=out}}) was installed just below the {{convert|80–90|foot|m|adj=on}} stairway and high above the {{convert|60–70|foot|m|adj=on}} stairway;<ref name=HABSdrawings />{{rp|sheet 25}}<ref name=Jacob />{{rp|52}} during the second phase of construction a stone with a horizontal line and the phrase "top of statue on Capitol" was installed on the {{convert|330|foot|m|adj=on}} level.<ref name=HABSdrawings />{{rp|sheet 30}}<ref>{{cite web|url=http://hdl.loc.gov/loc.pnp/hhh.dc0261/photos.027296p|title=Inscription at level 330 – Washington Monument, High ground West of Fifteenth Street, Northwest, between Independence & Constitution Avenues, Washington, District of Columbia, DC|work=loc.gov|year=1994}}</ref>

The ''Historic Structure Report'' (HSR, 2004) named 194 "memorial stones" by level, including both height stones.<ref name=HSR />{{rp|4{{hyphen}}17{{ndash}}4{{hyphen}}20, 5{{hyphen}}6, "194" on 4{{hyphen}}17 <!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering -->}} Jacob (2005) described in detail and pictured 193 "commemorative stones", including the {{convert|100|foot|m}} stone but not the [[United States Capitol|Capitol]] stone.<ref name=Jacob>Judith M. Jacob, [https://www.nps.gov/parkhistory/online_books/wamo/stones.pdf ''The Washington Monument: A technical history and catalog of the commemorative stones''] , 2005.</ref>{{rp|"193" on 1}} The ''Historic American Buildings Survey'' (HABS, 1994) showed the location of 193 "memorial stones" but did not describe or name any. HABS showed both height stones but did not show one stone not yet installed in 1994.<ref name=HABSdrawings />{{rp|sheets 22–25, 28–30}} <!-- HABS text 13 has 198, apparent misprint for 193 --> Olszewski (1971) named 190 "memorial stones" by level, including the Capitol stone but not the 100-foot stone. Olszewski did not include three stones not yet installed in 1971.<ref name=Olszewski />{{rp|chp 6, app D, "190" in chp 6}}

Of 194 stones, 94 are marble, 40 are granite, 29 are limestone, 8 are sandstone, with 23 miscellaneous types, including stones with two types of material and those whose materials are not identified.{{efn-ua |Material of the memorial stones is that named as "original material" by Judith Jacob, regardless of the material given in her "documentation" for the same stone. Some stones have small amounts of black paint, gold or silver within their letters. Six memorial stones are composed of significant amounts of two types of material each, the first stone and the second stone, lead or bronze. The material of seven memorial stones is not identified, including that of the Capitol stone.<ref name=Jacob />}} Unusual materials include [[native copper]] ([[Michigan]]),<ref name=Jacob />{{rp|147}} [[catlinite|pipestone]] ([[Minnesota]]),<ref name=Jacob />{{rp|153}} [[petrified wood]] ([[Arizona]]),<ref name=Jacob />{{rp|213}} and [[jadeite]] ([[Alaska]]).<ref name=Jacob />{{rp|220}}  The stones vary in size from about {{convert|1.5|ft|m}} square ([[Carthage]]){{efn-ua | The Carthage stone was the last memorial stone installed in the monument, in 2000.<ref>[https://web.archive.org/web/20150403075024/http://www.nps.gov/nama/learn/news/upload/October-10.pdf "The Washington Monument's Inner Jewels"], nps.gov</ref> <!-- end of efn-ua --> }} to about {{convert|6|x|8|ft|m}} ([[Philadelphia]] and New York City).<ref name=Jacob />{{rp|3, 90, 124, 218}}

==== Specific inscribed stones ====
[[Utah]] contributed one stone as a territory and another as a state, both with inscriptions that include its pre-territorial name, [[State of Deseret|Deseret]], both located on the {{convert|220|foot|m|adj=on}} level.<ref name=Jacob />{{rp|154–155}}

A stone at the {{convert|240|foot|m|adj=on}} level of the monument is inscribed in {{langx|cy|Fy Iaith, Fy Ngwlad, Fy Nghenedl, Cymry am byth}} (My Language, My Country, My Nation, Welsh forever). The stone, imported from Wales, was donated by Welsh citizens of [[New York (state)|New York]].<ref name=Jacob />{{rp|170}}<ref>''[https://books.google.com/books?id=cXgOAQAAMAAJ&dq=%22Fy+iaith%22&pg=RA1-PA139 The Cambrian]'', vol. XVII, p. 139. 1897.</ref> Two other stones were presented by the Sunday Schools of the [[Methodist Episcopal]] Church in New York and the Sabbath School children of the Methodist Episcopal Church in [[Philadelphia]]—the former quotes from  the Bible verse Proverbs 10:7, "The memory of the just is blessed".<ref name=Jacob />{{rp|190, 192}}

[[Ottoman Empire|Ottoman]] [[Sultan]] [[Abdul Mejid I]] donated $30,000 toward the construction of the Washington Monument as a symbol of peace between the Ottomans and the Americans. The stone containing the [[Ottoman Turkish|Turkish]] inscriptions commemorating this event is on the {{convert|190|foot|m|adj=on}} level. The abbreviated translation of the inscriptions states, "So as to strengthen the friendship between the two countries. Abdul-Mejid Kahn has also had his name written on the monument to Washington."<ref name=Jacob />{{rp|128}} 

One stone was donated by the [[Ryukyu Kingdom]] and brought back by Commodore [[Matthew C. Perry]],<ref>Kerr, George H. ''Okinawa: The History of an Island People''. (revised ed.) Tokyo: Tuttle Publishing, 2003. p337n.</ref> but never arrived in Washington (it was replaced in 1989).<ref name=Jacob />{{rp|210}}
Many of the stones donated for the monument carried inscriptions that did not commemorate George Washington. For example, one from the [[Templars of Honor and Temperance]] stated "We will not make, buy, sell, or use as a beverage, any spiritous or malt liquors, Wine, Cider, or any other Alcoholic Liquor."<ref name=Jacob />{{rp|140}} (George Washington himself had owned a whiskey distillery which operated at [[Mount Vernon]] after he left the presidency.<ref>{{cite book |last1=Ferling |first1=John E. |title=The First of Men: A Life of George Washington |date=1988 |publisher=Oxford University Press |location=New York |isbn=0-19-974227-8 |page=488 |url=https://books.google.com/books?id=o6NoAgAAQBAJ&pg=PA488|access-date=August 22, 2015}}</ref>)

===Walls===
[[File:Washington Monument rubble at 150 feet.png|thumb|upright=1|Cross section of rubble in shaft at 150-feet and typical of rubble below 150 feet|alt=Showing about 85 irregular large stones in mortar between empty shaft well and outer marble veneer]]
[[File:Washington Monument Marble Types.jpg|thumb|left|The three types (quarries) of marble used for the monument walls.]]The bottom section of {{convert|152|feet|m}} was built between 1848 and 1854 under the direction of William Dougherty. It uses white [[Cockeysville Marble]] from the Texas Quarry, a still-active quarry in [[Cockeysville, Maryland]].<ref name="Hannibal">{{cite journal |last=Hannibal |first=Joseph T. |date=June 22, 2020 |title=Cockeysville marble: a heritage stone from Maryland, USA |journal=[[Geological Society]]  |volume=486 |issue=1 |pages=229–249 |doi=10.1144/sp486-2019-1 |bibcode=2020GSLSP.486..229H |url=https://www.lyellcollection.org/doi/abs/10.1144/sp486-2019-1 }}</ref><ref name="BSNC">{{cite web |title=Building stones of our nation's capital |work=[[USGS]] |date= |access-date=2025-08-01 |url=https://pubs.usgs.gov/gip/stones/stones4.html }}</ref> During the second phase in 1879–1880, eight feet of white marble from Sheffield, Massachusetts, were laid above the "Texas" marble; this was halted due to quality control problems.<ref name="BSNC" /> The third and final phase of {{convert|390|feet|m}} is marble from the [[Beaver Dam (Maryland)|Beaver Dam]] quarry adjacent to the Texas quarry (1880–1884).<ref name="Hannibal" /><ref name="BSNC" /> The marble here was a warmer shade than the starker white of the Texas quarry.<ref name="Hannibal" /><ref name="Torres" />{{rp|63}}<ref>{{cite web |url=https://archive.org/details/TheHistoryOfTheMarbleQuarriesInBaltimoreCountyMaryland |title=The history of the marble quarries in Baltimore County, Maryland |author=William D. Purdum |date=March 5, 1940 |access-date=June 27, 2014}}</ref> The three different shades of marble can be distinguished on the monument.<ref name="BSNC" /> Engineers used three different systems to measure the monument's levels. The height of the marble walls was measured in {{convert|2|foot|adj=on}} increments, the pyramid-shaped top was measured in {{convert|4|foot|adj=on}} increments, and the stair landings were marked in {{convert|10|foot|adj=on}} increments. Complicating matters, the starting "zero point" for the staircase was different from the one used for the walls, and these references even shifted slightly when construction resumed for the second phase.<ref name="NGS2015" /><ref name="HSR" /><ref name="HABSdrawings" /><ref name="Casey1884" />

Since there was a long hiatus between the first phase and the last two phases, the monument has a complex [[superstructure]]. Around the {{convert|150|foot|adj=on}} level, the inner walls slope slightly outward, causing the hollow shaft inside to widen from about {{convert|25|feet|m}} square to over {{convert|31|feet|m}} square. Above this level, the monument's upper section has thinner walls. The lowest part of the upper section has walls measuring {{convert|8|feet|m}} thick, which featured distinctively rounded corners; these walls gradually tapered to {{convert|1+1/2|feet|m|spell=in}} thick at the top. The weight of this upper portion alone is {{convert|21,260|LT}}. In total, the monument's interior walls rise to a height of just over {{convert|500|feet|m}}.<ref name=NGS2015 /><ref name=HSR /><ref name=HABSdrawings /><ref name=Casey1884 />

During the first phase of construction, the monument's walls were built with a less refined technique. While the outer surface is made of thick marble stones arranged in {{convert|2|ft|m|adj=mid|-high}} rows, the core of the walls was filled with a random assortment of [[bluestone]] rubble, all held together by mortar. At its base, this first section is {{convert|55|feet|m}} square with massive {{convert|15|ft|m|adj=mid|-thick}} walls, and this lower portion alone weighs nearly {{convert|22,400|LT}}. During the second phase, engineers used precisely cut blocks of marble and granite laid in an orderly, interlocking pattern with thick, stable joints. For strength, the marble exterior was initially backed-filled by granite blocks. As the monument rose, the builders gradually transitioned to using marble for the interior as well, until the structure above the {{convert|450|foot|adj=on}} level was made entirely of solid marble blocks.<ref name="HSR" />{{rp|B-49}}<ref name="HABSdrawings" />{{rp|sheets 7–30}}<ref name="Torres" />{{rp|18–19, 23, 105–6}}<ref name="Casey1884" /> 

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===Pinnacle===

==== Pyramidion ====
[[File:Washington Monument pyramidion rib structure.png|thumb|upright=1|Rib structure of pyramidion with letter designations for courses]]
The [[pyramidion]], atop the monument, has a marble capstone shaped like a truncated pyramid, with a cubical keystone projecting from its base and a deep groove surrounding the keystone. The [[#Aluminum apex|aluminum apex]] replaces its truncated top. The inside upper edges of the topmost slabs on the four faces of the pyramidion rest on the keystone and in the groove. It has a large vertical hole through which a {{convert|1.5|in|cm|adj=on}} threaded copper rod passes and screws into the base of the apex, which used to form part of its [[#Lightning protection|lightning protection system]]. The keystone and groove occupy so much of its base that only a small horizontal area near its outer edge remains. The weight of the capstone is transferred to both the inner and outer portions of the [[shiplap]] upper edges of the slabs. It weighs {{convert|3300|lb|kg}}, is {{convert|5|ft|2|in|m}} high from its base to its top, and is {{convert|3|ft|cm|0}} square at its base.<ref name=Torres />{{rp|85}}<ref name=Evaluation>{{cite web |title=1993 Evaluation of the Washington Monument (1 of 5) |publisher=National Park Service |url=https://parkplanning.nps.gov/document.cfm?parkID=427&projectID=31299&documentID=43344}}</ref>{{rp|80}}

The marble pyramidion has an extremely complex construction to save weight yet remain strong. Its surface slabs or panels are usually only {{convert|7|in|cm|0}} thick (with small thick and thin portions) and generally do not support the weight of slabs above them, instead transferring their own weight via {{convert|1|ft|cm|0|adj=on}} wide internal marble ribs to the shaft's walls. The slabs are generally {{convert|7|ft|m|0}} wide and {{convert|4|ft|4|in|m|0}} high with a {{convert|2|in|cm|0|adj=on}} vertical overlap (shiplap) to prevent water from entering the horizontal joints. Twelve such courses, the internal ribs, the marble capstone, and the aluminum apex comprise the pyramidion. Its height is {{convert|55|ft|0|in|m|2}}. <!-- b = a cot A = ((34'5+1/2")/2) cot (34°48'/2) = 54'11+3/4" ≈ 55', not 55'5+1/8" --> Its weight is {{convert|300|LT|ST t|0|abbr=off}}.<ref name=Casey1884 /> The slope of the walls of the pyramidion is 17°24' from the vertical.<ref name=Casey1885 /> <!-- 17°24' = 34°48'/2; 17°24' = arctan(((34'5+5/8")/2)/55'), A pyramidion height of 55' is consistent with 17°24', but 55'5+1/8" is not. --> There are twelve ribs, three per wall, which spring from the {{convert|470|ft|m|1|adj=on}} level, all being integrated into the walls up to the {{convert|500|ft|m|1|adj=on}} level. All are free standing above 500 feet, relying on [[mortise and tenon]] joints to attach neighboring stones. The eight corner ribs terminate six courses above the shaft, each corner rib resting on its neighboring corner rib via a [[miter joint]], forming four corner arches. Each such arch supports a pair of square corner stones, one above the other totaling one course in height. Each corner rib is linked to the nearest center rib at the sixth course via a marble tie beam. The four center ribs terminate eight courses above the shaft at a marble cruciform (cross shaped) keystone, forming two main arches that cross each other. Two stones, each one-course high, are mounted on each of the four ribs, supporting two additional courses above the cruciform keystone, leaving two courses to support the capstone's weight by themselves.<ref name=HSR />{{rp|3{{hyphen}}8{{ndash}}3{{hyphen}}11}}<ref name=Earthquake />{{rp|6–10}}<ref name=Seismic>{{cite web |title=Washington Monument Seismic Report without appendices |pages=10–16 |website=Washington Monument Seismic Study |publisher=National Park Service |url=https://parkplanning.nps.gov/document.cfm?parkID=427&projectID=40394&documentID=49361 |access-date=June 14, 2016}}</ref>

The observation floor (nominally the 500-foot level) is {{convert|499|ft|4+1/2|in|m|2}} <!-- 499' 9+7/8" – 6+5/8" + 1+1/4" --> above the entry lobby floor or lowest landing level. It is {{convert|1+1/4|in|cm}} above the marble base of the pyramidion and the top of the shaft walls.<ref name=NGS2015 />{{rp|56, 58, 65}}<ref name=HABSdrawings />{{rp|sheet 7, 31–35}}<ref name=Casey1884 />

Four pairs of {{convert|3|ft|cm|adj=on}} wide observation windows are provided, spaced {{convert|4|ft|cm|0}} apart, inner stone edge to edge, all just above the lowest course of slabs (504-foot level). Six are {{convert|1|ft|6|in|cm}} high while two on the east face are {{convert|2|ft|cm}} high for easier egress. All were originally provided with thin marble shutters in a bronze frame each of which could be opened inward, one left and the other right per wall.<ref name=HSR />{{rp|3{{hyphen}}11}}<!-- hyphenated page is one page, not a range, because book uses page within chapter numbering --> After two people committed suicide by jumping through the open windows in the 1920s, hinged horizontal iron bars were added to them in 1929.<ref name=HSR />{{rp|3{{hyphen}}14}}<!-- hyphenated page is one page, not a range, because book uses page within chapter numbering --><ref name=Torres />{{rp|85, 102}} A ninth opening in a slab on the south face just below the capstone is provided for access to the outside of the pyramidion. It is covered by a stone slab which is internally removable. In 1931, four red aircraft warning lights were installed, one per face in one of its observation windows. Pilots complained that they could not be easily seen, so the monument was floodlit on all sides as well.<ref name=HSR />{{rp|2{{hyphen}}14, B{{hyphen}}39, B{{hyphen}}41, B{{hyphen}}52{{ndash}}B{{hyphen}}53}}<!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering --> In 1958, eight {{convert|14|in|cm|adj=on}} diameter holes for new red aircraft warning lights were bored, one above each window near the top edge of the fourth course of slabs (516-foot level) in the pyramidion.<ref name=HSR />{{rp|2{{hyphen}}28, 3{{hyphen}}15, B{{hyphen}}55}}<!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering --><ref name=HABSdrawings />{{rp|sheet 12}} In 1958 the observation windows were glazed with shatterproof glass. In 1974–1976, they were glazed with bulletproof glass and the shutters removed. New bulletproof glass was installed during 1997–2000.<ref name=HSR />{{rp|3{{hyphen}}16, 3{{hyphen}}18, B{{hyphen}}49}}<!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering -->

The pyramidion has two inscriptions, neither of which is regarded as a memorial stone. One is the year "1884" on the underside of the cruciform keystone; the other is at the same level as that keystone on the north face of the west center rib containing the names and titles of the four highest ranked builders. Its inscription ([[Media:Washington Monument inscription interior pyramidion.png|"Chief Engineer ..."]]) is almost identical to the inscription on the south face of the aluminum apex except for "U.S.", which is part of the phrase "14th U.S. Infantry" in the inscription inside the pyramidion, but the apex has only "14th Infantry". Additionally, the internal inscription does not use cursive writing and all letters in all names are capitals.<ref name=HABSdrawings />{{rp|sheet 35}}<ref name=Earthquake />{{rp|8}}

==== Aluminum apex ====
[[File:Aluminum apex Repaired 1934.png|thumb|upright=1|Aluminum apex showing inscriptions on its east (left) and north (right) faces]]
The aluminum apex, composed of a metal that at the time was as rare and valuable as silver, was cast by [[William Frishmuth]] of [[Philadelphia]].<ref name="Binczewski" /> At the time of casting, it was the largest piece of aluminum in the world. Before the installation, it was put on public display at [[Tiffany's]] in New York City and stepped over by visitors who could say they had "stepped over the top of the Washington Monument". It was {{convert|8.9|in|cm}} tall before {{convert|3/8|in|cm|0}} was vaporized from its tip by lightning strikes during 1885–1934, when it was protected from further damage by tall lightning rods surrounding it. Its base is {{convert|5.6|in|cm}} square. The angle between opposite sides at its tip is 34°48'. It weighed {{convert|100|oz|kg|2}} before lightning strikes removed a small amount of aluminum from its tip and sides.<ref name="Casey1885" /> Spectral analysis in 1934 showed that it was composed of 97.87% aluminum with the rest impurities.<ref name="Binczewski" /> It has a shallow depression in its base to match a slightly raised area atop the small upper surface of the marble capstone, which aligns the sides of the apex with those of the capstone, and the downward protruding lip around that area prevents water from entering the joint.<ref name="Torres" />{{rp|83–84}} It has a large hole in the center of its base to receive a threaded {{convert|1.5|in|cm|adj=on}} diameter copper rod which attaches it to the monument and used to form part of the lightning protection system.<ref name="Torres" />{{rp|91}} In 2015 the National Geodetic Survey reported the coordinates of the 1&nbsp;mm dimple atop the aluminum apex as {{coord|38|53|22.08920|N|77|2|6.92910|W|display=inline}} (WGS 84).<ref name="NGS2015" />{{rp|6, 82, 86}}

The four faces of the external aluminum apex all bear inscriptions in [[cursive]] writing (Snell [[Round hand]]), which are incised into the aluminum.<ref name="Binczewski" /> The apex was inscribed on site after it was delivered. Most inscriptions are the original 1884 inscriptions, except for the top three lines on the east face which were added in 1934. From 1885 to 1934 a wide gold-plated copper band that held eight short lightning rods, two per side but not at its corners, covered most of the inscriptions, which were damaged and illegible as shown in the accompanying picture made in 1934. A new band including eight long lightning rods, one at each corner and one at the middle of each side, was added in 1934 and removed and discarded in 2013. The inscriptions that it covered were still damaged and illegible in 2013.<ref name="NGS2015" />{{rp|90–95}}

The following table shows legible inscriptions in {{font color|#0000FF|blue}} and illegible inscriptions in {{font color|#B60000|red}}; these colors do not appear on the actual apex, nor are they to scale.<ref name="NGS2015" />{{rp|93}}
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{| class="wikitable" style="margin: 1em auto 1em auto;"
|-
! North face !! West face !! South face !! East face
|-
| align="center" style="white-space:nowrap; padding:1em;" | {{font color|#0000FF|2=Joint Commission<br />at<br />Setting of Cap Stone.<br />—————}} <!-- only a short line is used, not a line the width of the window --><br />{{font color|#B60000|2=Chester A. Arthur.<br />W. W. Corcoran, Chairman.<br />M. E. Bell.<br />Edward Clark.<br />{{font color|#0000FF|2=John Newton.<br />Act of August 2, 1876.}}}}
| align="center" style="white-space:nowrap; padding:1em;" |<br /><br /><br />{{font color|#0000FF|2=Corner Stone Laid}}<br />{{font color|#B60000|2=on Bed of Foundation<br />July 4, 1848.<br />First Stone at Height of<br />152&nbsp;feet laid<br />August 7, 1880.}}<br />{{font color|#0000FF|2=Capstone set December 6, 1884.}}
| align="center" style="white-space:nowrap; padding:1em;" | {{font color|#0000FF|2=Chief Engineer<br />and<br />Architect,<br />Thos. Lincoln Casey,}}<br />{{font color|#B60000|2=Colonel, Corps of Engineers.<br />Assistants:<br />George W. Davis, Captain, 14th Infantry.<br />Bernard R. Green, Civil Engineer.<br />Master Mechanic,<br />P. H. McLaughlin.}}
| align="center" style="white-space:nowrap; padding:1em;" | {{font color|#0000FF|2=Repaired 1934,<br />National Park Service,<br />Department of the Interior.}}<br /><br /><br />{{font color|#B60000|2=Laus Deo.}}<br /><br /><br /><br />
|}

Although Harvey (1903),<ref name="Harvey" />{{rp|295}} Olszewski (1971),<ref name="Olszewski" />{{rp|app C}} Torres (1984),<ref name="Torres" />{{rp|82, 84}} and the ''Historic Structure Report'' (2004),<ref name="HSR" />{{rp|4{{hyphen}}6{{ndash}}4{{hyphen}}7 <!-- page within chapter numbering -->}} refer to the original 1884 inscriptions, the National Geodetic Survey (2015)<ref name="NGS2015" />{{rp|90–95}} refers to both the 1884 and 1934 inscriptions. All sources print them according to their own editorial rules, resulting in excessive capitalization (Harvey, Olszewski, and NGS) and inappropriate line breaks. No printed source uses cursive writing, although pictures of the apex clearly show that it was used for both the 1884 and 1934 inscriptions.<ref name="NGS2015" />{{rp|92–95}}<ref>{{Cite web |last=Horydczak |first=Theodor |date=October 22, 1920 |title=Washington Monument. Cap stone of Washington Monument without lightning rods |url=https://www.loc.gov/pictures/resource/thc.5a48088 |url-status=dead |archiveurl=https://web.archive.org/web/20161009141739/http://loc.gov/pictures/resource/thc.5a48088/ |archivedate=October 9, 2016 |website=www.loc.gov}}</ref><ref>{{Cite web |last=Horydczak |first=Theodor |date=October 22, 1920 |title=Washington Monument. Cap stone of Washington Monument without lightning rods II |url=https://www.loc.gov/pictures/resource/thc.5a48091 |url-status=dead |archiveurl=https://web.archive.org/web/20160515041623/http://www.loc.gov/pictures/resource/thc.5a48091/ |archivedate=May 15, 2016 |website=www.loc.gov}}</ref>

A replica displayed on the 490-foot level uses totally different line breaks from those on the external apex—it also omits the 1934 inscriptions. In October 2007, it was discovered that the display of this replica was positioned so that the Laus Deo (Latin for "praise be to God") inscription could not be seen and Laus Deo was omitted from the placard describing the apex. The National Park Service rectified the omission by creating a new display.<ref>{{cite web |title=A Monumental Omission |url=http://www.nationaltreasures.org/CR_MonOmi.html |url-status=usurped |archive-url=https://web.archive.org/web/20081002203216/http://www.nationaltreasures.org/CR_MonOmi.html |archive-date=October 2, 2008 |access-date=January 31, 2013 |publisher=Nationaltreasures.org}}</ref>

==== Lightning protection ====
[[File:Three-lighting-strikes-washingtondc-night - West Virginia - ForestWander.jpg|thumb|upright=1|Lightning strikes near the Washington Monument]]
The pyramidion was originally designed with an {{convert|8.9|in|cm|adj=on}} tall inscribed aluminum apex which served as a single lightning rod, installed {{nowrap|December 6, 1884}}. Lightning damaged the marble blocks of the pyramidion on {{nowrap|June 5, 1885}},<ref>M., [https://books.google.com/books?id=Pw5M1V3DEDUC&pg=PA517 "The Washington Monument, and the Lightning Stroke of June 5"] {{webarchive|url=https://web.archive.org/web/20160902113718/https://books.google.com/books?id=Pw5M1V3DEDUC&pg=PA517|date=September 2, 2016}}, ''Science'' 5 (1885) 517–518.</ref> so a net of gold-plated copper rods supporting 200 {{convert|3|in|cm|adj=on}} gold-plated, platinum-tipped copper points spaced every {{convert|5|ft|m}} was installed over the entire pyramidion.<ref name="HSR" />{{rp|3{{hyphen}}10{{ndash}}3{{hyphen}}11, 3{{hyphen}}15, <!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering --> figs 3.17, 3.23}}<ref name="Olszewski" />{{rp|chp 6}}<ref name="Torres" />{{rp|91–92}} The original net included a gold-plated copper band attached to the aluminum apex by four large set screws which supported eight closely spaced vertical points that did not protrude above the apex. In 1934 these eight short points were lengthened to extend them above the apex by {{convert|6|in|cm}}.<ref>Gabriel Escobar, "Workers prepare to fill a tall order", ''Washington Post'' Tuesday, October 13, 1998, page B1.</ref> In 2013 this original system was removed and discarded. It was replaced by only two thick solid aluminum lightning rods protruding above the tip of the apex by about {{convert|1|ft|m|1|spell=in}} attached to the east and west sides of the marble capstone just below the apex.<ref name="NGS2015" />{{rp|23, 26}}<ref name="AerialAmerica" />

Until it was removed, the original lightning protection system was connected to the tops of the four iron columns supporting the elevator with large copper rods. Even though the aluminum apex is still connected to the columns with large copper rods, it is no longer part of the lightning protection system because it is now disconnected from the present lightning rods which shield it. The two lightning rods present since 2013 are connected to the iron columns with two large braided aluminum cables leading down the surface of the pyramidion near its southeast and northwest corners. They enter the pyramidion at its base, where they are tied together (electrically shorted) via large braided aluminum cables encircling the pyramidion {{convert|2|ft|m|1|spell=in}} above its base.<ref name="AerialAmerica" /> The bottom of the iron columns are connected to ground water below the monument via four large copper rods that pass through a {{convert|2|ft|m|1|adj=on}} square well half filled with sand in the center of the foundation. The effectiveness of the lightning protection system has not been affected by a significant draw down of the [[water table]] since 1884 because the soil's water content remains roughly 20% both above and below the height of the water table.<ref>Jean-Louis Briaud ''et al'', [http://casehistories.geoengineer.org/volume/volume1/issue3/IJGCH_1_3_3.pdf "The Washington Monument case history"] {{webarchive|url=https://web.archive.org/web/20160801004347/http://casehistories.geoengineer.org/volume/volume1/issue3/IJGCH_1_3_3.pdf|date=August 1, 2016}}, ''International Journal of Geoengineering Case Histories'' 1 (2009) 170–188, pp. 176–179.</ref>

===Stairs and elevator===
[[File:Sections - Washington Monument, High ground West of Fifteenth Street, Northwest, between Independence and Constitution Avenues, Washington, District of Columbia, DC HABS DC,WASH,2- (sheet 31 of 37).png|thumb|right|upright=1|North interior wall with its stairs and their wire screening]]
The monument is filled with ironwork, consisting of its stairs, elevator columns and associated tie beams, none of which supports the weight of the stonework. It was redesigned in 1958 to reduce congestion and improve the flow of visitors. Originally, visitors entered and exited the west side of the elevator on the observation floor, causing congestion. So the large landing at the 490-foot level was expanded to a full floor and the original spiral stair in the northeast corner between the {{convert|490|and|500|foot|m|1|adj=on}}  levels was replaced by two spiral stairs in the northeast and southeast corners. Now visitors exit the elevator on the observation floor, then walk down either spiral stair before reboarding the elevator for their trip back down.<ref name=HSR />{{rp|fig 3.31}}

The main stairs spiral up the interior walls from the entry lobby floor to the elevator reboarding floor at the {{convert|490|foot|m|adj=on}} level. The elevator occupies the center of the shaft well from the entry lobby to the observation floor, with an elevator machine room (installed 1925–26) whose floor is {{convert|18|ft|10|in|m|2}} above the observation floor and an elevator pit (excavated 1879) whose floor is {{convert|9|ft|m|2}} <!-- 7'10" + 14+1/8" --> below the entry lobby floor.<ref name=HABSdrawings />{{rp|sheet 31–35}}<ref name=Torres />{{rp|61, 74}} The stairs and elevator are supported by four wrought iron columns each. The four supporting the stairs extend from the entry lobby floor to the observation floor and were set at the corners of a {{convert|15|ft|8|in|m|2|adj=on}} square. The four supporting the elevator extend from the floor of the elevator pit to {{convert|14|ft|m|1}} above the observation floor and were set at the corners of a {{convert|9|ft|9+1/2|in|m|1|adj=on}} square.<ref name=HSR />{{rp|3{{hyphen}}6}}<!-- hyphenated page is one page, not a range, because book uses page within chapter numbering --> The weight of the ironwork is {{convert|275|LT|ST t|0|abbr=off}}.<ref name=Casey1884 /> [[Cast iron]], [[wrought iron]], and steel were all used. The two small spiral stairs installed in 1958 are aluminum.<ref name=HSR />

Most landings occupy the entire east and west interior walls every {{convert|10|ft|m|2}} from and including the east landing at the {{convert|30|foot|m|1|adj=on}} level up to the west landing at the {{convert|480|foot|m|adj=on}} level, east then west alternately. Three stairs with small landings rise from the entry lobby floor to the {{convert|30|foot|m|1|adj=on}} level successively along the north, west and south interior walls. Landings from the {{convert|30|foot|m}} level up to the {{convert|150|foot|m}} level are {{convert|3|ft|2+1/4|in|m|2}} by {{convert|25|ft|1|in|m|2}}, while landings from the {{convert|160|foot|m|adj=on}} level to the {{convert|480|foot|m|adj=on}} level are {{convert|7|ft|10+3/4|in|m|2}} by {{convert|31|ft|5+1/2|in|m|2}}. All stairs are on the north and south walls except for the aforementioned west stair between the {{convert|10-20|foot|m|2|adj=on}} levels, and the two spiral stairs.<ref name=HSR />

About one quarter of visitors chose to ascend the monument using the stairs when they were available. They were closed to up traffic in 1971, and then closed to all traffic except by special arrangement in 1976.<ref name=HSR />{{rp|3{{hyphen}}18}}<!-- hyphenated page is one page, not a range, because book uses page within chapter numbering --><ref name=Torres />{{rp|101}} The stairs had 898 steps until 1958, consisting of 18 [[stair riser|risers]] in each of the 49 main stairs plus 16 risers in the spiral stair.<ref name=Olszewski />{{rp|chp 7}}<ref name="Snell">Charles W. Snell, [https://www.nps.gov/parkhistory/online_books/wamo/wamo_history.pdf A Brief History of the Washington Monument and Grounds, 1783–1978]  (1978) 17–19.</ref>{{rp|18}} Since 1958 the stairs have had 897 risers if only one spiral stair is counted because both spiral stairs now have 15 risers each.<ref name=HABSdrawings />{{rp|sheets 6, 31–35}}<ref name=Torres />{{rp|72}} These figures do not include two additional steps in the entry passage that were covered up in 1975 by a ramp and its inward horizontal extension to meet the higher (since 1886) entry lobby floor. One step was {{convert|3.2|ft|m|0}} away from the outer walls and the other was at the end of the passage, {{convert|15|ft|m|1}} away from the outer walls.<ref name=HSR />{{rp|3{{hyphen}}17{{ndash}}3{{hyphen}}18, figs 3.11, 3.32{{ndash}}3.33, 3.39}}<!-- page within chapter numbering -->

As initially constructed, the interior was relatively open with two-rail [[handrail]]s, but a couple of suicides and an accidental fall prompted the addition of tall wire screening {{convert|7|ft|m|1}} high with a large diamond mesh on the inside edge of the stairs and landings in 1929. The original steam powered elevator, which took 10 to 12 minutes to ascend to the observation floor, was replaced by an electric elevator powered by an on-site [[dynamo]] in 1901 which took five minutes to ascend. The monument was connected to the [[electrical grid]] in 1923, allowing the installation of a modern electric elevator in 1925–26 which took 70 seconds. The latter was replaced in 1958 and again in 1998 by 70-second elevators.<ref name=HSR />{{rp|2{{hyphen}}13, 2{{hyphen}}15, 3{{hyphen}}20{{ndash}}3{{hyphen}}21, B{{hyphen}}44, B{{hyphen}}47, B{{hyphen}}48}}<!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering --><ref name=Harvey />{{rp|102, 107–8}} From 1997 to 2000, the wire screening at three platforms was replaced by large glass panels to allow visitors on the elevator to view three clusters of memorial stones that were synchronously lit as the elevator automatically slowed while passing them during its descent.<ref name=HSR />{{rp|3{{hyphen}}21, 4{{hyphen}}16}}<!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering -->

=== Height ===
[[File:Worlds_tallest_buildings,_1884.jpg|thumb|The Principal High Buildings of the Old World design from 1884 with Washington Monument as the tallest structure represented]]
The monument stands {{convert|554|ft|7+11/32|in|m}} tall according to the National Geodetic Survey (measured 2013–14) or {{convert|555|ft|5+1/8|in|m}} tall according to the [[National Park Service]] (measured 1884).{{efn-ua  | name=height}} In 1975, a ramp covered two steps at the entrance to the monument, so the ground next to the ramp was raised to match its height, reducing the remaining height to the monument's apex. It is both the world's tallest predominantly stone structure and the world's tallest obelisk. It is the third tallest monumental column in the world, trailing only the [[Juche Tower]] in [[Pyongyang]] (560 ft/170 m) and the [[San Jacinto Monument]] in [[Houston, Texas]] (567.31 ft/172.92 m), though neither of those are all stone nor true obelisks.{{efn-ua | name=columns}} The tallest [[masonry structure]] in the world is the brick [[Anaconda Smelter Stack]] in [[Montana]] at {{convert|585|ft|1+1/2|in|m|2}} tall; this includes a {{convert|30|ft|m|1|adj=on}} non-masonry concrete foundation, leaving the stack's brick chimney at {{convert|555|ft|1+1/2|in|m|2}} tall. If the monument's aluminum apex is also discounted, then the stack's masonry portion is {{convert|15|in|cm|0}} taller than the monument's masonry portion.<ref name="Kelly" />{{efn-ua | name=height}}{{efn-ua |name=Anaconda | [[Masonry]], by definition, includes manufactured brick, natural stone units, and [[concrete masonry unit]]s. Taller stacks or chimneys are made of [[reinforced concrete]]. See the [[list of tallest towers]] (designed for regular public access), and the [[list of tallest chimneys]] (not designed for regular public access).}}<!-- end of efn-ua -->

===Miscellaneous details===
The weight of the above ground portion of the monument is {{convert|44208|LT|ST t|0|abbr=off}}, <!-- Long tons were used in the 19th century source documents. --> whereas its total weight, including the foundation below ground and any earth above it that is within its outer perimeter is {{convert|81120|LT|ST t|0|abbr=off}}. The total number of blocks in the monument, including all marble, granite and gneiss blocks, whether externally or internally visible or hidden from view within the walls or old foundation is over 36,000.<ref name="FAQ" /> {{clear}}

== Grounds ==
The monument is surrounded by an earthen terrace {{convert|60|ft|m|0}} wide, with its top at the base of the walls and steeply-sloped sides. This was constructed in 1880–81 over the reinforced foundation. During 1887–88, a knoll was constructed around the terrace tapering out roughly {{convert|300|ft|m|-1}} onto the surrounding terrain. This earthen terrace and knoll buttress the foundation.<ref name="Casey1884" />

===Flags===
[[File:Overhead view of Washington Monument.jpg|thumb|upright=1|50 American flags representing the 50 U.S. states surround the Washington Monument.]]
Fifty [[Flag of the United States|U.S. national flags]], one representing each state, are flown 24 hours a day around a large circle centered on the monument. Forty-eight American flags (one for each state then in existence) were flown on wooden flag poles on Washington's birthday since 1920 and later on Independence Day, Memorial Day, and other special occasions until early 1958. Both the flags and flag poles were removed and stored between these days. In 1958 fifty {{convert|25|ft|m|adj=on}} <!-- foot or more below ground? HABS text has 24' on 15 --> tall aluminum flag poles (anticipating Alaska and Hawaii) were installed, evenly spaced around a {{convert|260|ft|m|adj=on}} diameter circle. During 2004–05, the diameter of the circle was reduced to {{convert|240|ft|m}}. Since Washington's birthday in 1958, 48 U.S. flags were flown on a daily basis, increasing to 49 flags on {{nowrap|July 4, 1959}}, and then to 50 flags since {{nowrap|July 4, 1960}}. When fewer than 50 flags were flown, only the flag poles in use were placed into base receptacles, and all flags were removed and stored overnight. Since {{nowrap|July 4, 1971}}, fifty U.S. flags have flown 24 hours a day.<ref name=HSR />{{rp|2{{hyphen}}14{{ndash}}2{{hyphen}}15, 4{{hyphen}}1{{ndash}}4{{hyphen}}2, B{{hyphen}}35{{ndash}}B{{hyphen}}36 <!-- page within chapter numbering -->}}<ref name=HABSdrawings />{{rp|sheet 3}}<ref name=flags>{{Cite web|url=https://www.nps.gov/parkhistory/online_books/wamo/flag.pdf|title=Michael D. Hoover, ''The origins and history of the Washington Monument flag display'', 1992}}</ref>

===Approximate vesica piscis===
[[File:Washington Monument - night.JPG|thumb|upright=1|The monument stands at a height of about 555 feet.]]
During the 2004 grounds renovation, two partially overlapping large circles were added to the landscaping with the obelisk in their intersection. The lens shape formed by such an intersection is called [[vesica piscis]] when two same-radius circles overlap, with the center of each lying on the perimeter of the other.<ref>{{cite journal |last=Fletcher | first=Rachel | doi=10.1007/s00004-004-0021-8 | issue=2 | journal=Nexus Network Journal | pages=95–110 | title=Musings on the Vesica Piscis | volume=6 | year=2004| doi-access=free }}.</ref> 

== Visitation ==
The Washington Monument attracted enormous crowds before it officially opened. For six months after its dedication, 10,041 people climbed the stairs to the top. After the [[elevator]] that had been used to raise building materials was altered to carry passengers, the number of visitors grew rapidly, and an average of 55,000 people per month were going to the top by 1888, only three years after its completion and dedication.<ref>{{cite web |title=Determining the Facts Reading 3: Finishing the Monument |url=http://www.nps.gov/nr/twhp/wwwlps/lessons/62wash/62facts4.htm |url-status=dead |archive-url=https://web.archive.org/web/20070901072132/http://www.nps.gov/nr/twhp/wwwlps/lessons/62wash/62facts4.htm |archive-date=September 1, 2007 |access-date=January 15, 2015 |publisher=nps.gov}}</ref> The annual visitor count peaked at an average of 1.1&nbsp;million people between 1979 and 1997. From 2005 to 2010, when restrictions were placed on the number of visitors allowed per day, the Washington Monument had an annual average of 631,000 visitors.<ref>{{cite news |date=August 24, 2011 |title=Monthly Visitors to the Washington Monument |url=https://www.nytimes.com/interactive/2011/08/25/us/20110825-monthly-visitors-to-the-washington-monument.html?ref=us |access-date=January 15, 2015 |newspaper=The New York Times}}</ref> The national memorial was listed on the [[National Register of Historic Places]] on October 15, 1966, as with all historic areas administered by the [[National Park Service]] (an agency of the [[United States Department of the Interior|U.S. Department of the Interior]]) at the time.<ref>{{NRISref|2007a}}</ref>

===Security===
[[File:Buildings in Washington, D.C. 01907 (cropped) ha-ha wall 2.JPG|thumb|upright=1|A low-profile [[ha-ha]] wall surrounds the monument.]]
In 2001, a temporary visitor security screening center{{snd}}a one-story cube of wood around a metal frame{{snd}}was added to the east entrance of the Washington Monument in the wake of the [[September 11 attacks]]. Visitors passed through metal detectors and bomb-sniffing sensors prior to entering the monument.<ref name=screening>[http://www.ncpc.gov/DocumentDepot/Actions_Recommendations/2014March/Washington_Monument_Visitor_Screening_Facility_Recommendation_6176_March2014_.pdf National Park Service and National Capital Planning Commission. "Visitor Screening Facility, Washington Monument Between 14th and 17th Streets, NW and Constitution Avenue, NW and the Tidal Basin." Executive Director's Recommendation. NCPC File Number 6176. March 6, 2014, pp. 5, 7] {{webarchive |url=https://web.archive.org/web/20160304092420/http://www.ncpc.gov/DocumentDepot/Actions_Recommendations/2014March/Washington_Monument_Visitor_Screening_Facility_Recommendation_6176_March2014_.pdf |date=March 4, 2016 }}. Retrieved March 7, 2014.</ref>

In 2019<ref name="Lefrak j645" /> a new {{convert|785|sqft|m2|adj=on}} two-story screening facility opened. Its exterior walls are slightly frosted, consisting of an outer sheet of [[bulletproof glass]] or [[polycarbonate]], a metal mesh insert, and another sheet of bulletproof glass. The inner sheet consists of two sheets of [[laminated glass]]; a {{convert|0.5|in|cm|adj=on}} airspace between the inner and outer glass walls provides thermal insultion. [[Geothermal heat pump]]s on the north side of the monument heat and cool the facility. The new facility also incorporates a staff office. The structure is designed such that it can be removed without damage to the monument.<ref>[http://www.bizjournals.com/washington/breaking_ground/2014/03/heres-where-youll-queue-to-visit-the.html Neibauer, Michael. "Here's Where You'll Queue to Visit the Washington Monument." ''Washington Business Journal.'' March 7, 2014] {{webarchive |url=https://web.archive.org/web/20160829220910/http://www.bizjournals.com/washington/breaking_ground/2014/03/heres-where-youll-queue-to-visit-the.html |date=August 29, 2016 }}.</ref>

A recessed trench wall known as a [[ha-ha]] has been built to minimize the visual impact of a security barrier surrounding the monument. After the [[September 11 attacks]] and another unrelated threat at the monument, authorities had put up a circle of temporary [[Jersey barrier]]s to block the approach of vehicles. This barrier was replaced by a low {{convert|30 |in|cm|adj=on}} granite stone wall that doubles as a bench and also incorporates lighting. Designed by the famed landscape architect [[Laurie Olin]], the installation received the 2005 Park/Landscape Award of Merit from the [[American Society of Landscape Architects]].<ref>[http://www.theolinstudio.com/flash#/projects/type/washington-monument Washington Monument]  {{webarchive|url=https://web.archive.org/web/20160430151505/http://www.theolinstudio.com/flash |date=April 30, 2016 }} (from the [[OLIN]] website)</ref><ref>[<!-- http://www.asla.org/land/2006/0410/olin.html -->https://www.asla.org/awards/2008/08winners/236.html Monument Security] (from the [[American Society of Landscape Architects]] website, ASLA awards 2006)</ref><ref>{{cite book| title = Risk Management Series: Site and Urban Design for Security|date=January 27, 2013 |pages=4–17| publisher = U. S. Department Security, Federal Emergency Agency| url =https://books.google.com/books?id=Atd4Pg2RXgQC&pg=SA4-PA18}}</ref>

==See also==
{{Portal|United States|Architecture}}
* [[Washington Monument syndrome]]
* [[Architecture of Washington, D.C.]]
* [[List of national memorials of the United States]]
* [[List of public art in Washington, D.C., Ward 2]]
* [[List of tallest freestanding structures]]
* [[List of tallest structures]]
* [[List of tallest structures built before the 20th century]]
*[[Adams Memorial]] (proposed)
*[[Bunker Hill Monument]]
*[[Benjamin Franklin National Memorial]]
*[[Jefferson Memorial]]
*[[James Madison Memorial Building]]
*[[George Mason Memorial]]
*[[Memorial to the 56 Signers of the Declaration of Independence]]
* [[Presidential memorials in the United States]]
* [[Tuckahoe marble]]
* [[Yule Marble]]

==Notes==
{{reflist|group=upper-alpha}}

==References==
{{Reflist}}

== External links ==
{{commons and category}}
{{NIE Poster}}
* Official NPS website: [https://www.nps.gov/wamo Washington Monument]
* {{cite web|url=http://www.nationalmall.org/sites-subpage-washington.php|title=Trust for the National Mall: Washington Monument|publisher=Trust for the National Mall|url-status=dead|archive-url=https://web.archive.org/web/20110611031625/http://www.nationalmall.org/sites-subpage-washington.php|archive-date=June 11, 2011}}
* [https://www.nytimes.com/learning/general/onthisday/harp/0221.html ''Harper's Weekly'' cartoon, February 21, 1885, the day of formal dedication]
* [http://memory.loc.gov/ammem/today/dec06.html Today in History{{snd}}December 6]
* {{Structurae|id=20000087|title=Washington National Monument}}
* {{HABS |survey=DC-428 |id=dc0261 |title=Washington Monument}}
* {{HAER |survey=DC-5 |id=dc0968 |title=Washington Monument}}
* [http://anthropology.si.edu/cm/krakker_wash_monument.htm Prehistory on the Mall at the Washington Monument]

{{S-start}}
{{S-ach|rec}}
{{S-bef|before=[[Lincoln Cathedral]]}}
{{S-ttl|title=[[History of the world's tallest structures|World's tallest structure ever built]]|years=1884–1889<br /><small>169.29&nbsp;m</small>}}
{{S-aft|rows=2|after=[[Eiffel Tower]]}}
{{S-bef|before=[[Cologne Cathedral]]}}
{{S-ttl|title=[[History of the world's tallest structures|World's tallest existing structure]]|years=1884–1889}}
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{{George Washington}}
{{Washington DC landmarks}}
{{Protected Areas of the District of Columbia}}
{{authority control}}

{{Good article}}

[[Category:1888 establishments in Washington, D.C.]]
[[Category:Buildings and structures completed in 1888]]
[[Category:Former world's tallest buildings]]
[[Category:Historic American Buildings Survey in Washington, D.C.]]
[[Category:Historic American Engineering Record in Washington, D.C.]]
[[Category:Historic Civil Engineering Landmarks]]
[[Category:IUCN protected area errors]]
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[[Category:National memorials of the United States]]
[[Category:Obelisks in the United States]]
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