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The Pentagon is the
headquarters Headquarters (commonly referred to as HQ) denotes the location where most, if not all, of the important functions of an organization are coordinated. In the United States, the corporate headquarters represents the entity at the center or the to ...
building of the
United States Department of Defense The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national secu ...
. It was constructed on an accelerated schedule during
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. As a symbol of the
U.S. military The United States Armed Forces are the military forces of the United States. The armed forces consists of six service branches: the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard. The president of the United States is the ...
, the phrase ''The Pentagon'' is often used as a
metonym Metonymy () is a figure of speech in which a concept is referred to by the name of something closely associated with that thing or concept. Etymology The words ''metonymy'' and ''metonym'' come from grc, μετωνυμία, 'a change of name' ...
for the Department of Defense and its leadership. Located in
Arlington County, Virginia Arlington County is a County (United States), county in the Virginia, Commonwealth of Virginia. The county is situated in Northern Virginia on the southwestern bank of the Potomac River directly across from the Washington, D.C., District of Co ...
, across the
Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augus ...
from
Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...
, the building was designed by American architect
George Bergstrom George Edwin Bergstrom (March 12, 1876 – June 17, 1955) was an American architect who designed The Pentagon in Arlington County, Virginia. Biography George Edwin Bergstrom was born in Neenah, Wisconsin, of Norwegian immigrant ancestry. His ...
and built by contractor
John McShain John McShain (December 21, 1896 – September 9, 1989) was a American building contractor known as "The Man Who Built Washington". Born in Philadelphia, Pennsylvania, the son of Irish immigrants, McShain graduated from St. Joseph's Preparatory S ...
. Ground was broken on 11 September 1941, and the building was dedicated on 15 January 1943. General
Brehon Somervell Brehon Burke Somervell (9 May 1892 – 13 February 1955) was a general in the United States Army and Commanding General of the Army Service Forces in World War II. As such he was responsible for the U.S. Army's logistics. Following his death, ' ...
provided the major impetus to gain Congressional approval for the project; Colonel
Leslie Groves Lieutenant General Leslie Richard Groves Jr. (17 August 1896 – 13 July 1970) was a United States Army Corps of Engineers officer who oversaw the construction of the Pentagon and directed the Manhattan Project, a top secret research project ...
was responsible for overseeing the project for the
U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...
Corps of Engineers, which supervised it. The Pentagon is the world's largest office building, with about of
floor space In architecture, construction, and real estate, floor area, floor space, or floorspace is the area (measured as square feet or square metres) taken up by a building or part of it. The ways of defining "floor area" depend on what factors of the buil ...
, of which are used as offices. Some 23,000
military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
and
civilian Civilians under international humanitarian law are "persons who are not members of the armed forces" and they are not "combatants if they carry arms openly and respect the laws and customs of war". It is slightly different from a non-combatant, b ...
employees, and another 3,000 non-defense support personnel, work in the Pentagon. It has five sides, five floors above ground, two basement levels, and five ring corridors per floor with a total of of corridors. The central pentagonal plaza is nicknamed "
ground zero In relation to nuclear explosions and other large bombs, ground zero (also called surface zero) is the point on the Earth's surface closest to a detonation. In the case of an explosion above the ground, ''ground zero'' is the point on the ground ...
" on the presumption that it would be a prime target in a
nuclear war Nuclear warfare, also known as atomic warfare, is a theoretical military conflict or prepared political strategy that deploys nuclear weaponry. Nuclear weapons are weapons of mass destruction; in contrast to conventional warfare, nuclear w ...
. In 2001, the Pentagon was damaged during the
September 11 attacks The September 11 attacks, commonly known as 9/11, were four coordinated suicide terrorist attacks carried out by al-Qaeda against the United States on Tuesday, September 11, 2001. That morning, nineteen terrorists hijacked four commercia ...
. Five
al-Qaeda Al-Qaeda (; , ) is an Islamic extremism, Islamic extremist organization composed of Salafist jihadists. Its members are mostly composed of Arab, Arabs, but also include other peoples. Al-Qaeda has mounted attacks on civilian and military ta ...
hijackers flew
American Airlines Flight 77 American Airlines Flight 77 was a scheduled American Airlines domestic transcontinental passenger flight from Washington Dulles International Airport in Dulles, Virginia, to Los Angeles International Airport in Los Angeles, California. The Boe ...
into the western side of the building, killing themselves and 184 others: 59 on the airplane and 125 in the Pentagon. It was the first significant foreign attack on Washington's governmental facilities since the city was burned by the British during the
War of 1812 The War of 1812 (18 June 1812 – 17 February 1815) was fought by the United States of America and its indigenous allies against the United Kingdom and its allies in British North America, with limited participation by Spain in Florida. It bega ...
. Following the attacks, the western side of the building was repaired, with a small indoor memorial and chapel added at the point of impact. An outdoor memorial dedicated to the Pentagon victims of 9/11 opened in 2008.


Layout and facilities

The Pentagon building spans , and includes an additional as a central courtyard. Starting with the north side and moving
clockwise Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite ...
, its five façade entrances are the Mall Terrace, the River Terrace, the Concourse (or Metro Station), the South Parking, and the Heliport. On the north side of the building, the Mall Entrance, which also features a portico, leads out to a terrace that is used for ceremonies. The River Entrance, which features a
portico A portico is a porch leading to the entrance of a building, or extended as a colonnade, with a roof structure over a walkway, supported by columns or enclosed by walls. This idea was widely used in ancient Greece and has influenced many cult ...
projecting out , is on the northeast side, overlooking the lagoon and facing Washington. A stepped terrace on the River Entrance leads down to the lagoon; and a landing dock was used until the late 1960s to ferry personnel between
Bolling Air Force Base Bolling Air Force Base or Bolling AFB was a United States Air Force base in Washington, D.C. In 2010, it was merged with Naval Support Facility Anacostia to form Joint Base Anacostia–Bolling. From its beginning, the installation has hosted elem ...
and the Pentagon. The main entrance for visitors is on the southeast side, as are the Pentagon Metro station and the bus station. There is also a concourse on the southeast side of the second floor of the building, which contains a mini-shopping mall. The south parking lot adjoins the southwest façade, and the west side of the Pentagon faces Washington Boulevard. The concentric rings are designated from the center out as "A" through "E" (with additional "F" and "G" rings in the basement). "E" Ring offices are the only ones with outside views and are generally occupied by senior officials. Office numbers go clockwise around each of the rings, and have two parts: a nearest-corridor number (1 to 10), followed by a bay number (00 to 99), so office numbers range from 100 to 1099. These corridors radiate out from the central courtyard, with corridor 1 beginning with the Concourse's south end. Each numbered radial corridor intersects with the corresponding numbered group of offices (for example, corridor 5 divides the 500 series office block). There are a number of historical displays in the building, particularly in the "A" and "E" rings. Subterranean floors in the Pentagon are lettered "B" for Basement and "M" for
Mezzanine A mezzanine (; or in Italian language, Italian, a ''mezzanino'') is an intermediate floor in a building which is partly open to the double-height ceilinged floor below, or which does not extend over the whole floorspace of the building, a loft ...
. The concourse is on the second floor at the Metro entrance. Above-ground floors are numbered 1 to 5. Room numbers are given as the floor, concentric ring, and office number (which is in turn the nearest corridor number followed by the bay number). Thus, office 2B315 is on the second floor, B ring, and nearest to corridor 3 (between corridors 2 and 3). One way to get to this office would be to go to the second floor, get to the A (innermost) ring, go to and take corridor 3, and then turn left on ring B to get to bay 15. It is possible for a person to walk between any two points in the Pentagon in less than ten minutes, though the most optimal route may involve a brisk walk, routing through the open-air central courtyard, or both. The complex includes eating and exercise facilities, and meditation and prayer rooms. Just south of the Pentagon are
Pentagon City Pentagon City is an unincorporated neighborhood (also called an "urban village") located in the southeast portion of Arlington County, Virginia, near The Pentagon and Arlington National Cemetery. Location Pentagon City is located less than a mil ...
and Crystal City, extensive shopping, business, and high-density residential districts in Arlington.
Arlington National Cemetery Arlington National Cemetery is one of two national cemeteries run by the United States Army. Nearly 400,000 people are buried in its 639 acres (259 ha) in Arlington, Virginia. There are about 30 funerals conducted on weekdays and 7 held on Sa ...
is to the north. The Pentagon is surrounded by the relatively complex
Pentagon road network The Pentagon road network is a system of highways, mostly freeways, built by the United States federal government in the early 1940s to serve the Pentagon in northern Virginia. The roads, transferred to the Commonwealth of Virginia in 1964, are ...
. The Pentagon has six Washington, DC, ZIP Codes (despite its location in Virginia): The Secretary of Defense, the Joint Chiefs of Staff, and the four service branches each have their own ZIP Code.


History


Background

Before the Pentagon was built, the
United States Department of War The United States Department of War, also called the War Department (and occasionally War Office in the early years), was the United States Cabinet department originally responsible for the operation and maintenance of the United States Army, a ...
was headquartered in the
Munitions Building The Main Navy and Munitions Buildings were constructed in 1918 along Constitution Avenue (then known as B Street) on Washington, D.C.'s National Mall (Potomac Park) as the largest of a set of temporary war buildings on the National Mall. Both b ...
, a temporary structure erected during
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
along
Constitution Avenue Constitution Avenue is a major east–west street in the northwest and northeast quadrants of the city of Washington, D.C., in the United States. It was originally known as B Street, and its western section was greatly lengthened and widened betw ...
on the
National Mall The National Mall is a Landscape architecture, landscaped park near the Downtown, Washington, D.C., downtown area of Washington, D.C., the capital city of the United States. It contains and borders a number of museums of the Smithsonian Institut ...
. The War Department, which was a civilian agency created to administer the
U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...
, was spread out in additional temporary buildings on the National Mall, as well as dozens of other buildings in Washington, D.C.,
Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...
and
Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...
. In the late 1930s, during the Great Depression and federal construction program, a new War Department Building was constructed at 21st and C Streets in
Foggy Bottom Foggy Bottom is one of the oldest late 18th- and 19th-century neighborhoods in Washington, D.C., located west of the White House and downtown Washington, in the Northwest quadrant. It is bounded roughly by 17th Street NW to the east, Rock Cr ...
but, upon completion, the new building did not solve the department's space problem. It became the headquarters of the
Department of State The United States Department of State (DOS), or State Department, is an executive department of the U.S. federal government responsible for the country's foreign policy and relations. Equivalent to the ministry of foreign affairs of other nati ...
. When
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
broke out in Europe in 1939, the War Department rapidly expanded to deal with current issues and in anticipation that the United States would be drawn into the conflict. Secretary of War
Henry L. Stimson Henry Lewis Stimson (September 21, 1867 – October 20, 1950) was an American statesman, lawyer, and Republican Party politician. Over his long career, he emerged as a leading figure in U.S. foreign policy by serving in both Republican and D ...
found the situation unacceptable, with the Munitions Building overcrowded and department offices spread out in additional sites. Stimson told U.S. President
Franklin D. Roosevelt Franklin Delano Roosevelt (; ; January 30, 1882April 12, 1945), often referred to by his initials FDR, was an American politician and attorney who served as the 32nd president of the United States from 1933 until his death in 1945. As the ...
in May 1941 that the War Department needed additional space. On 17 July 1941, a congressional hearing took place, organized by Congressman Clifton Woodrum (D-VA), regarding proposals for new War Department buildings. Woodrum pressed Brigadier General Eugene Reybold, who was representing the War Department at the hearing, for an "overall solution" to the department's "space problem", rather than building yet more temporary buildings. Reybold agreed to report back to the congressman within five days. The War Department called upon its construction chief, General
Brehon Somervell Brehon Burke Somervell (9 May 1892 – 13 February 1955) was a general in the United States Army and Commanding General of the Army Service Forces in World War II. As such he was responsible for the U.S. Army's logistics. Following his death, ' ...
, to come up with a plan.


Planning

Government officials agreed that the War Department building, officially designated Federal Office Building No 1, should be constructed across the
Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augus ...
, in
Arlington County, Virginia Arlington County is a County (United States), county in the Virginia, Commonwealth of Virginia. The county is situated in Northern Virginia on the southwestern bank of the Potomac River directly across from the Washington, D.C., District of Co ...
. Requirements for the new building were that it be no more than four stories tall, and that it use a minimal amount of steel to reserve that resource for war needs. The requirements meant that, instead of rising vertically, the building would be sprawling over a large area. Possible sites for the building included the Department of Agriculture's
Arlington Experimental Farm Arlington Experimental Farm was a former federal agricultural research farm in Alexandria, Virginia that opened in 1900. It was established by an Act of Congress, moving the Department of Agriculture's main research from the National Mall to Arl ...
, adjacent to
Arlington National Cemetery Arlington National Cemetery is one of two national cemeteries run by the United States Army. Nearly 400,000 people are buried in its 639 acres (259 ha) in Arlington, Virginia. There are about 30 funerals conducted on weekdays and 7 held on Sa ...
, and the obsolete
Hoover Field Hoover Field was an early airport serving the city of Washington, D.C. It was constructed as a private airfield in 1925, but opened to public commercial use on July 16, 1926. It was located in Arlington, Virginia, near the intersection of the H ...
site. The site originally chosen was
Arlington Farms Arlington Farms was a temporary housing complex for female civil servants and service members during World War II. Built in 1942–1943 by the United States Government's Federal Works Agency (FWA), Arlington Farms was located on the former site o ...
, which had an asymmetric, roughly pentagonal shape, so the building was planned accordingly as an irregular pentagon. Concerned that the new building could obstruct the view of Washington, D.C., from Arlington Cemetery, President Roosevelt ended up selecting the Hoover Airport site instead. The building retained the pentagonal layout because Roosevelt liked it and a major redesign at that stage would have been costly. Freed of the constraints of the Arlington Farms site, the building was modified as a regular
pentagon In geometry, a pentagon (from the Greek πέντε ''pente'' meaning ''five'' and γωνία ''gonia'' meaning ''angle'') is any five-sided polygon or 5-gon. The sum of the internal angles in a simple pentagon is 540°. A pentagon may be simpl ...
. It resembled star forts constructed during the gunpowder age. On 28 July,
Congress A congress is a formal meeting of the representatives of different countries, constituent states, organizations, trade unions, political parties, or other groups. The term originated in Late Middle English to denote an encounter (meeting of a ...
authorized funding for a new Department of War building in Arlington, which would house the entire department under one roof. President Roosevelt officially approved of the Hoover Airport site on 2 September. While the project went through the approval process in late July 1941, Somervell selected the contractors, including John McShain, Inc. of
Philadelphia Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Sinc ...
, which had built
Washington National Airport Ronald Reagan Washington National Airport , sometimes referred to colloquially as National Airport, Washington National, Reagan National Airport, DCA, Reagan, or simply National, is an international airport in Arlington County, Virginia, across ...
in Arlington, the
Jefferson Memorial The Jefferson Memorial is a presidential memorial built in Washington, D.C. between 1939 and 1943 in honor of Thomas Jefferson, the principal author of the United States Declaration of Independence, a central intellectual force behind the Am ...
in Washington, and the
National Naval Medical Center National may refer to: Common uses * Nation or country ** Nationality – a ''national'' is a person who is subject to a nation, regardless of whether the person has full rights as a citizen Places in the United States * National, Maryland, ce ...
in
Bethesda, Maryland Bethesda () is an unincorporated, census-designated place in southern Montgomery County, Maryland. It is located just northwest of Washington, D.C. It takes its name from a local church, the Bethesda Meeting House (1820, rebuilt 1849), which in ...
, along with Wise Contracting Company, Inc. and Doyle and Russell, both from Virginia. In addition to the Hoover Airport site and other government-owned land, construction of the Pentagon required an additional , which were acquired at a cost of $2.2 million (equivalent to $ in ). The Hell's Bottom neighborhood, consisting of numerous pawnshops, factories, approximately 150 homes, and other buildings around Columbia Pike, was cleared to make way for the Pentagon. Later, of land were transferred to
Arlington National Cemetery Arlington National Cemetery is one of two national cemeteries run by the United States Army. Nearly 400,000 people are buried in its 639 acres (259 ha) in Arlington, Virginia. There are about 30 funerals conducted on weekdays and 7 held on Sa ...
and to
Fort Myer Fort Myer is the previous name used for a U.S. Army post next to Arlington National Cemetery in Arlington County, Virginia, and across the Potomac River from Washington, D.C. Founded during the American Civil War as Fort Cass and Fort Whipple, t ...
, leaving for the Pentagon.


Construction

Contracts totaling $31,100,000 (equivalent to $ in ) were finalized with McShain and the other contractors on 11 September 1941, and ground was broken for the Pentagon the same day. Among the design requirements, Somervell required the structural design to accommodate floor loads of up to , which was done in case the building became a records storage facility at some time after the end of the current war. A minimal amount of steel was used as it was in short supply during World War II. Instead, the Pentagon was built as a reinforced concrete structure, using 680,000 tons of sand dredged from the
Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augus ...
, and a lagoon was created beneath the Pentagon's river entrance. To minimize steel usage, concrete ramps were built rather than installing elevators.
Indiana limestone Indiana limestone — also known as Bedford limestone in the building trade — has long been an economically important building material, particularly for monumental public structures. Indiana limestone is a more common term for Salem Limestone, ...
was used for the building's façade. Architectural and structural design work for the Pentagon proceeded simultaneously with construction, with initial drawings provided in early October 1941, and most of the design work completed by 1 June 1942. At times the construction work got ahead of the design, with different materials used than those specified in the plans. Pressure to speed up design and construction intensified after the
attack on Pearl Harbor The attack on Pearl HarborAlso known as the Battle of Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States against the naval base at Pearl Harbor in Honolulu, Territory of Hawaii, j ...
on 7 December 1941, with Somervell demanding that of space at the Pentagon be available for occupation by 1 April 1943. David J. Witmer replaced Bergstrom as chief architect on 11 April after Bergstrom resigned. Unrelated to the Pentagon project, he was charged with improper conduct while having served as president of the
American Institute of Architects The American Institute of Architects (AIA) is a professional organization for architects in the United States. Headquartered in Washington, D.C., the AIA offers education, government advocacy, community redevelopment, and public outreach to su ...
. Construction was completed 15 January 1943. Soil conditions of the siteon the
Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augus ...
floodplainpresented challenges, as did the varying
elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...
s across the site, which ranged from above
sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...
. Two retaining walls were built to compensate for the elevation variations, and cast-in-place piles were used to deal with the soil conditions. Construction of the Pentagon was completed in approximately 16 months at a total cost of $83 million (equivalent to $ in ). The building's approximate height is , and each of the five sides is in length. The building was built wedge by wedge; each wedge was occupied as soon as it was completed, even as construction continued on the remaining wedges. The Pentagon was designed in accordance with the
racial segregation Racial segregation is the systematic separation of people into race (human classification), racial or other Ethnicity, ethnic groups in daily life. Racial segregation can amount to the international crime of apartheid and a crimes against hum ...
laws in force in the state of Virginia at the time, with separate eating and lavatory accommodations for white and black persons. While the sets of lavatories were side by side, the dining areas for blacks were located in the basement. When Roosevelt visited the facility before its dedication, he ordered removal of the "Whites Only" signs in segregated areas. When the Governor of Virginia protested, Roosevelt's administration responded that the Pentagon, although on Virginia land, was under Federal jurisdiction. In addition, its military and civilian Federal employees were going to comply with the President's policies. As a result, the Pentagon was the only building in Virginia where racial segregation laws were not enforced (these laws were not overturned until 1965). The side-by-side sets of restrooms still exist, but have been integrated in practice since the building was occupied.


Hall of Heroes

On the building's main concourse is the Hall of Heroes, opened 1968 and dedicated to the more than 3,460 recipients of the
Medal of Honor The Medal of Honor (MOH) is the United States Armed Forces' highest military decoration and is awarded to recognize American soldiers, sailors, marines, airmen, guardians and coast guardsmen who have distinguished themselves by acts of valor. ...
, the United States' highest military decoration. The three versions of the Medal of HonorArmy, Sea Service (for the
Marine Corps Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refle ...
,
Navy A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral zone, littoral, or ocean-borne combat operations and ...
, and
Coast Guard A coast guard or coastguard is a maritime security organization of a particular country. The term embraces wide range of responsibilities in different countries, from being a heavily armed military force with customs and security duties to ...
), and Air Force (for the
Air Force An air force – in the broadest sense – is the national military branch that primarily conducts aerial warfare. More specifically, it is the branch of a nation's armed services that is responsible for aerial warfare as distinct from an a ...
and
Space Force A space force is a military branch of a nation's armed forces that conducts military operations in outer space and space warfare. The world's first space force was the Russian Space Forces, established in 1992 as an independent military service. ...
)are on display along with the names of recipients. The Hall is also used for promotions, retirements, and other ceremonies.


Renovation

From 1998 to 2011, the Pentagon was completely gutted and reconstructed in phases to bring it up to modern standards and improve security and efficiency.
Asbestos Asbestos () is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic "fibrils" that can be released into the atmosphere b ...
was removed and all office windows were sealed. As originally built, most Pentagon office space consisted of open bays which spanned an entire ring. These offices used cross-ventilation from operable windows instead of air conditioning for cooling. Gradually, bays were subdivided into private offices with many using window air conditioning units. With renovations now complete, the new space includes a return to open office bays, and a new Universal Space Plan of standardized office furniture and partitions developed by Studios Architecture. Pentagon tours were suspended during the
COVID-19 pandemic The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identif ...
.


Incidents


Protests

During the late 1960s, the Pentagon became a focal point for protests against the
Vietnam War The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...
. A group of 2,500 women, organized by
Women Strike for Peace Women Strike for Peace (WSP, also known as Women for Peace) was a women's peace activist group in the United States. In 1961, nearing the height of the Cold War, around 50,000 women marched in 60 cities around the United States to demonstrate aga ...
, demonstrated outside Secretary of Defense
Robert S. McNamara Robert Strange McNamara (; June 9, 1916 – July 6, 2009) was an American business executive and the eighth United States Secretary of Defense, serving from 1961 to 1968 under Presidents John F. Kennedy and Lyndon B. Johnson. He remains the ...
's office at the Pentagon on 15 February 1967. In May 1967, a group of 20 demonstrators held a sit-in outside the Joint Chiefs of Staff's office, which lasted four days before they were arrested. In one of the better known incidents, on 21 October 1967, some 35,000 anti-war protesters organized by the
National Mobilization Committee to End the War in Vietnam The Spring Mobilization Committee to End the War in Vietnam, which became the National Mobilization Committee to End the War in Vietnam, was a coalition of American antiwar activists formed in November 1966 to organize large demonstrations in o ...
, gathered for a demonstration at the Defense Department (the "March on the Pentagon"). They were confronted by some 2,500 armed soldiers. During the protest, a famous picture was taken, where George Harris placed
carnations ''Dianthus caryophyllus'' (), commonly known as the carnation or clove pink, is a species of ''Dianthus''. It is likely native to the Mediterranean region but its exact range is unknown due to extensive cultivation for the last 2,000 years.Med ...
into the soldiers' gun barrels. The march concluded with an attempt to "exorcise" the building. On 19 May 1972, the
Weather Underground Organization The Weather Underground was a far-left militant organization first active in 1969, founded on the Ann Arbor campus of the University of Michigan. Originally known as the Weathermen, the group was organized as a faction of Students for a Democr ...
bombed a fourth-floor women's restroom, in "retaliation" for the
Nixon administration Richard Nixon's tenure as the List of presidents of the United States, 37th president of the United States began with First inauguration of Richard Nixon, his first inauguration on January 20, 1969, and ended when he resigned on August 9, 1974 ...
's bombing of Hanoi in the final stages of the
Vietnam War The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...
. On 17 March 2007, 4,000 to 15,000 people (estimates vary significantly) protested the
Iraq War {{Infobox military conflict , conflict = Iraq War {{Nobold, {{lang, ar, حرب العراق (Arabic) {{Nobold, {{lang, ku, شەڕی عێراق (Kurdish languages, Kurdish) , partof = the Iraq conflict (2003–present), I ...
by marching from the
Lincoln Memorial The Lincoln Memorial is a U.S. national memorial built to honor the 16th president of the United States, Abraham Lincoln. It is on the western end of the National Mall in Washington, D.C., across from the Washington Monument, and is in the ...
to the Pentagon's north parking lot.


September 11, 2001 attacks

On
September 11, 2001 The September 11 attacks, commonly known as 9/11, were four coordinated suicide terrorist attacks carried out by al-Qaeda against the United States on Tuesday, September 11, 2001. That morning, nineteen terrorists hijacked four commerc ...
, coincidentally the 60th anniversary of the Pentagon's groundbreaking, five
al-Qaeda Al-Qaeda (; , ) is an Islamic extremism, Islamic extremist organization composed of Salafist jihadists. Its members are mostly composed of Arab, Arabs, but also include other peoples. Al-Qaeda has mounted attacks on civilian and military ta ...
affiliated
hijackers Hijacking may refer to: Common usage Computing and technology * Bluejacking, the unsolicited transmission of data via Bluetooth * Brandjacking, the unauthorized use of a company's brand * Browser hijacking * Clickjacking (including ''like ...
took control of
American Airlines Flight 77 American Airlines Flight 77 was a scheduled American Airlines domestic transcontinental passenger flight from Washington Dulles International Airport in Dulles, Virginia, to Los Angeles International Airport in Los Angeles, California. The Boe ...
, ''en route'' from
Washington Dulles International Airport Washington Dulles International Airport , typically referred to as Dulles International Airport, Dulles Airport, Washington Dulles, or simply Dulles ( ), is an international airport in the Mid-Atlantic (United States), Eastern United States, loc ...
to
Los Angeles International Airport Los Angeles International Airport , commonly referred to as LAX (with each letter pronounced individually), is the primary international airport serving Los Angeles, California and its surrounding metropolitan area. LAX is located in the W ...
, and deliberately crashed the
Boeing 757 The Boeing 757 is an American narrow-body airliner designed and built by Boeing Commercial Airplanes. The then-named 7N7, a twinjet successor for the 727 (a trijet), received its first orders in August 1978. The prototype completed its mai ...
airliner into the western side of the Pentagon at 9:37 am EDT as part of the
September 11 attacks The September 11 attacks, commonly known as 9/11, were four coordinated suicide terrorist attacks carried out by al-Qaeda against the United States on Tuesday, September 11, 2001. That morning, nineteen terrorists hijacked four commercia ...
. The impact of the plane severely damaged the outer ring of one wing of the building and caused its partial collapse. At the time of the attacks, the Pentagon was under renovation and many offices were unoccupied, resulting in fewer casualties. Only 800 of 4,500 people who would have been in the area were there because of the work. Furthermore, the area hit, on the side of the Heliport façade, was the section best prepared for such an attack. The renovation there, improvements which resulted from the
Oklahoma City bombing The Oklahoma City bombing was a domestic terrorist truck bombing of the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, United States, on April 19, 1995. Perpetrated by two anti-government extremists, Timothy McVeigh and Terry N ...
, had nearly been completed. It was the only area of the Pentagon with a sprinkler system, and it had been reconstructed with a web of steel columns and bars to withstand bomb blasts. The steel reinforcement, bolted together to form a continuous structure through all of the Pentagon's five floors, kept that section of the building from collapsing for 30 minutes—enough time for hundreds of people to crawl out to safety. The area struck by the plane also had blast-resistant windows— thick and each—that stayed intact during the crash and fire. It had fire doors that opened automatically and newly built exits that allowed people to get out. Contractors already involved with the renovation were given the added task of rebuilding the sections damaged in the attacks. This additional project was named the " Phoenix Project" and was charged with having the outermost offices of the damaged section occupied by 11 September 2002. When the damaged section of the Pentagon was repaired, a small indoor memorial and chapel were added at the point of impact. For the fifth anniversary of the September 11 attacks, a memorial of 184 beams of light shone up from the center courtyard of the Pentagon, one light for each victim of the attack. In addition, an American flag is hung each year on the side of the Pentagon damaged in the attacks, and the side of the building is illuminated at night with blue lights. After the attacks, plans were developed for an outdoor memorial, with construction underway in 2006. This
Pentagon Memorial The Pentagon Memorial, formally the National 9/11 Pentagon Memorial, located just southwest of The Pentagon in Arlington County, Virginia, across the Potomac River from Washington, D.C., is a permanent outdoor memorial to the 184 people who di ...
consists of a park on of land, containing 184 benches, one dedicated to each victim. The benches are aligned along the line of Flight 77 according to the victims' ages, from 3 to 71. The park opened to the public on 11 September 2008.


Gallery

File:Pentagon construction.jpg, View from northwest with construction underway, July 1942 File:The Pentagon US Department of Defense building.jpg, Southwesterly view (1998) with the
Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augus ...
and
Washington Monument The Washington Monument is an obelisk shaped building within the National Mall in Washington, D.C., built to commemorate George Washington, once commander-in-chief of the Continental Army (1775–1784) in the American Revolutionary War and the ...
in background File:Aerial view of the Pentagon during rescue operations post-September 11 attack.JPEG, Aftermath of 9/11 attacks File:Pentagon blue lights.jpg, 9/11 anniversary illumination, 2007 File:Pentagon Memorial-5089.jpg, Pentagon 9/11 Memorial


See also

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List of National Historic Landmarks in Virginia This is a list of National Historic Landmarks in Virginia. There are currently 123 National Historic Landmark, National Historic Landmarks (NHLs), and 2 former NHLs. Current landmarks The National Historic Landmarks (NHLs) are widely distributed ...
*
List of United States military bases This is a list of military installations owned or used by the United States Armed Forces currently located in the United States and around the world. This list details only current or recently closed facilities; some defunct facilities are f ...
*
National Register of Historic Places listings in Arlington County, Virginia __NOTOC__ This is a list of the National Register of Historic Places listings in Arlington County, Virginia. This is intended to be a complete list of the properties and districts on the National Register of Historic Places in Arlington County, ...
*
The Octagon The Octagon may refer to: *The Octagon, Christchurch, a former church in the central city of Christchurch, New Zealand *The Octagon, Dunedin, the city centre of Dunedin, New Zealand *The Octagon (Egypt), the headquarters of the Egyptian Ministry of ...
, headquarters of the Egyptian Ministry of Defense in the
New Administrative Capital The New Administrative Capital (NAC) ( ar, العاصمة الإدارية الجديدة, al-ʿĀṣima al-ʾIdārīya al-Gadīda) is a new urban community in Cairo Governorate, Egypt and a satellite of Cairo City. It is planned to be Egypt's ...
*
Pentagon Force Protection Agency The Pentagon Force Protection Agency (PFPA) is a federal law enforcement agency within the U.S. Department of Defense (DoD) charged with protecting and safeguarding the occupants, visitors, and infrastructure of The Pentagon, the Mark Center Bui ...


Notes


References


Citations


Sources

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External links


The Pentagon website
(archived version)
''Popular Mechanics'', March 1943, ''"Army's Giant Five-by-Five"''
one of earliest World War II articles on the Pentagon
Pentagon Force Protection Agency
nbsp;– ''The Washington Post'', 26 May 2007 * {{DEFAULTSORT:Pentagon Military installations in Virginia Military headquarters in the United States Buildings and structures in Arlington County, Virginia Government buildings completed in 1943 Government buildings on the National Register of Historic Places in Virginia National Historic Landmarks in Virginia National Register of Historic Places in Arlington County, Virginia American Airlines Flight 77 Articles containing video clips 1943 establishments in Virginia US September 11 attacks