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The Pentagon building -

The Pentagon is one of the most recognized buildings in the world. It serves as the headquarters of the United States Department of Defense.

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The Pentagon takes shape -

Ironically, construction on the Pentagon began on September 11, 1941.

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Concrete and sand -

With steel supplies requisitioned for the war effort, concrete was chosen to build the Pentagon, comprised, in part, from some 700,000 tons of sand dredged from the Potomac River.

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Built in double-quick time -

Work was completed on January 15, 1943, accelerated in part by the attack on Pearl Harbor on December 7, 1941 and the United States' entry into the Second World War. A back-breaking, multiple-shift, 24-hour-a-day construction schedule also contributed to its speedy inauguration. Pictured is the Pentagon during its construction in November 1942.

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Five-sided architectural wonder -

Named for its five sides, the Pentagon is the world's largest office building. It occupies 150 acres (6.5 million square feet) of floor space.

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Pentagon specifications -

The building stands 23 m (77 ft) above ground, or five stories. Each of its five sides is 280 m (921 ft) long. There are five ring corridors per floor, with more than 27 km (17 mi) of corridors.

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Presidential approval -

Why a five-sided building? In fact, the design for the Pentagon was conceived from earlier blueprints for a new War Department building that was to take shape on a site known as Arlington Farms, a piece of land roughly pentagonal in shape. In time, however, another site was chosen. But plans for the building, also pentagon-shaped, were so far advanced that altering the design was not practical. And in any case, President Franklin D. Roosevelt loved the idea. "I like it because nothing like it has ever been done that way before," Roosevelt was quoted as saying, commenting on the shape of the planned new War Department building.

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The costs involved -

The total cost of developing and building the Pentagon was over US$83 million, which included the land purchase, construction of outside facilities and the Pentagon Lagoon, and construction of the building itself. To put that figure into perspective, $83 million in 1943 is equivalent in purchasing power to approximately $1.3 billion in 2021.

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Pentagon personnel -

The Pentagon's first employees had in fact moved in on April 30, 1942, around nine months before the facility became fully operational. In the early years, not everyone had a telephone on their desk, so some messengers took to the long hallways on roller skates. Pictured are telephonists operating the Pentagon switchboard in the early 1950s.

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Post-Second World War -

Deemed too big to serve any practical purpose in peacetime, ideas of how to put the Pentagon to use after the Second World War included converting the building into a hospital or a university. A headquarters for the Veterans Administration was also mooted. But the US Army was not having any of it.

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Cold War threat -

In the post-Second World War era, the Pentagon's role was defined by growing Cold War tensions and rivalry between the United States and the Soviet Union. A nuclear conflict was a very frightening possibility. The Pentagon ultimately became the headquarters of the Army, Navy, and Air Force under the umbrella of the United States Department of Defense. Pictured is a North Atlantic Treaty Committee meeting taking place in the Pentagon on June 10, 1949.

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The Korean War -

The outbreak of the Korean War in 1950 put the Pentagon back on the highest alert. Pictured is General Douglas MacArthur (right) and his staff at the front lines above Suwon, Korea.

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Royal visitor -

The Korean War over, by the mid-1950s the Pentagon had become somewhat of a tourist attraction. It even had a royal visitor in the Queen Mother, who toured part of the facility with the First Lady, Mamie Eisenhower. The pair are pictured in the Pentagon pharmacy.

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Anti-Vietnam war protest -

In October 1967 the Pentagon became the focus of anti-Vietnam War protests. The building was seen as a symbol of America's growing military dominance in the world, and with it an increasingly belligerent stance in the Southeast Asian conflict. Pictured carrying graphically illustrated anti-Vietnamese war posters are members of the "Women's Strike for Peace" as they push their way to the doors of the Pentagon. The main doors of the building were locked for 30 minutes, as the women stormed the doors in an effort to gain entrance.

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Flower power -

In this famous image taken on October 21, 1967, George Harris sticks carnations in gun barrels during the antiwar demonstrations at the Pentagon. Some 35,000 protesters marched towards the Pentagon, to be met by armed federal troops. Fortunately not a shot was fired and no one was killed.

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The Pentagon Papers -

In 1971, small portions of the Report of the Office of the Secretary of Defense Vietnam Task Force commissioned by US Secretary of Defense Robert McNamara in 1967 were leaked to the press. Katharine Graham, publisher of The Washington Post, and Ben Bradlee, its executive editor (both pictured), appeared together at the US District Court in Washington, D.C., on June 21, 1971, following a hearing on the newspaper's request to publish what had by then become known as the Pentagon Papers, the secret documents detailing America's war in Vietnam. The classified documents were eventually released in their entirety in 2011.

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Crisis in the Gulf -

The launch of Operation Desert Shield in 1990 and the subsequent Gulf War saw the Pentagon take a central role in response to Iraqi leader Saddam Hussein's unprovoked invasion and annexation of Kuwait. Pictured is US Joints Chiefs of Staff General Colin Powell speaking to reporters at the Pentagon.

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National Historic Landmark -

In 1992, the Pentagon building was proclaimed a National Historic Landmark.

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The US government and Hollywood -

The US government and Hollywood have always been close. The first Oscar-winning picture, 'Wings,' from 1927, was a First World War movie made with support from the US Air Force.

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Filmmakers and the Pentagon -

Similarly, filmmakers and the Pentagon have long collaborated on projects to bring films authenticity and the Department of Defense (DOD) publicity. For example, the Pentagon provided the producers of 'Top Gun' (1986) with invaluable technical assistance. The movie was a box-office sensation and effectively served as a flashy, all-star US Navy recruitment picture.

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'Air Force One' (1997) -

The movie 'Air Force One' starring Harrison Ford as US President James Marshall was produced with the benefit of Pentagon input.

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'GoldenEye' (1995) -

In exchange for its assistance, the Pentagon will sometimes interfere with the production of a movie. In a scene from the Bond film 'GoldenEye,' DOD officials didn’t like the idea of an American admiral being duped and killed so easily. So the nationality of the official was changed to French.

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Renovation -

An extensive renovation and upgrading of the Pentagon building began in late 1994. Reconstruction was still taking place when this satellite image was taken of the Pentagon on September 7, 2001.

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September 11, 2001 -

Four days later, on the morning of September 11, 2001, coincidentally the 60th anniversary of the Pentagon's groundbreaking, a Boeing 757—American Airlines Flight 77—piloted by al-Qaeda-affiliated hijackers was deliberately crashed into the western side of the Pentagon.

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The attack of 9/11 -

At the time of the attacks and because the Pentagon was under renovation, many offices were unoccupied. However, the attack killed all 64 people on the plane, including the five hijackers, and 125 people in the Pentagon.

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Pentagon burning -

The Pentagon building was still burning after nightfall as the rescue and recovery operation continued.

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Reinforcements -

More Pentagon staff might have died were it not for the fact that the area hit, on the side of the Heliport facade, was the section best prepared for such an attack. Renovation of that area, complete with steel reinforcements, prevented it from completely collapsing for 30 minutes, allowing hundreds of people to crawl out to safety.

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Pentagon Memorial -

The Pentagon Memorial commemorates the 184 innocent victims of the September 11 attack on the Pentagon building. Memorial benches (184 of them), dedicated to each of the victims and organized in a timeline of their ages, are set on land right outside where the jetliner struck the building.

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Annual commemoration -

In addition to the permanent memorial, an American flag is unfurled every year on the illuminated side of the Pentagon damaged by the attack to commemorate the anniversary of the 9/11 terror attacks.

Sources: (History) (The Guardian) (Los Angeles Times) (Capitol Markets) (The Pentagon Tours) (Tampa Bay Times) (Department of Defense) (Academia)

See also: Tourist hubs targeted by terrorists since 9/11

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