In January 1943, while World War II raged in Europe and the Pacific, the U.S. military began to manage the war effort from the Pentagon, its newly finished headquarters in Arlington, Virginia. The gigantic edifice, which sits on the bank of the Potomac River outside of Washington, D.C., still serves as the nerve center of the Department of Defense. It is one of the largest office buildings in the world.
Before the Pentagon’s construction, the different parts of the War Department (as the Defense Department was called) were headquartered in scattered offices. Ground was broken in September 1941 and construction completed in only sixteen months at a cost of $83 million. The war had caused a shortage of steel, so engineers dredged 680,000 tons of sand and gravel from the Potomac and turned it into reinforced concrete for the building.
Virtually a city unto itself, the Pentagon covers 29 acres. It has 3.7 million square feet of space, three times the floor space of the Empire State Building. The U.S. Capitol building could fit into any one of its five wedge-shaped sections. About 23,000 people work at the Pentagon.
The five-sided building is designed in the form of five concentric rings. Despite its huge size and 17.5 miles of corridors, the Pentagon is one of the world’s most efficient office buildings. It takes only seven minutes to walk between any two points in the structure.
During the September 11, 2001, terrorist attacks, a hijacked jetliner slammed into the Pentagon, blowing a gaping hole in one side and killing 189 people. Construction crews worked around the clock for a year to repair the outer ring before the first anniversary of the attacks.