What is the Pentagon? (with pictures)

The Pentagon is a building located in Arlington County, Va., near Washington, D.C. that houses the headquarters of the United States Department of Defense. The building has a unique pentagonal shape which surrounds an open courtyard, and houses 23,000 civilian and military employees. The Pentagon is often used as a symbol of the American military complex, as the shape makes it readily recognizable. The Pentagon is sometimes compared to a small city, due to the size and complexity of the building. It houses the Joint Chiefs of Staff and Secretary of Defense along with the Army, Navy, Air Force, and Marines.

The Pentagon's unique shape makes it a highly efficient office building. Although the Pentagon has 3,705,793 square feet (1,129,526 meters) of office space, it is possible to reach most points in the building within 10 minutes, a remarkable architectural achievement. In a building which coordinates the armed forces of the United States along with organizations responsible for intelligence and security, workers often need to be able to access each other quickly.

The idea of the Pentagon was conceived in 1941, when Brigadier General Brehon Sommervell was trying to solve the problem of limited space for the Department of Defense, a serious issue in the Second World War. It was agreed that a new building was needed, and a groundbreaking ceremony took place on 11 September, 1941. It took just two years to complete the building on former marshlands along the outskirts of Washington, and the Pentagon was quickly filled with communications equipment and staff to coordinate the Department of Defense.

Seventeen separate office buildings were consolidated in the Pentagon in order to make it a central location. The building has a large number of fixtures and amenities to supply the staff, including 284 bathrooms, 16,250 lighting fixtures, and 7,754 windows. The iconic building is available for tours, although access is restricted to certain areas and particular times. The Pentagon complex is on a 583 acre square area of land, which includes 67 acres of parking space for employees.

60 years to the day after the ground was broken for the Pentagon, American Airlines Flight 77 was hijacked and flown into the western side of the Pentagon, killing 189 people immediately upon impact. The Pentagon was evacuated, along with other major buildings in the area. Repairs on the site began quickly, with the space fully usable less than a year after the terrorist attacks.