The Pentagon is the world's second largest office building, with about 6.5 million square feet (600,000 m 2) of floor space, of which 3.7 million square feet (340,000 m 2) are used as offices. Army Corps of Engineers, which supervised it. General Brehon Somervell provided the major impetus to gain Congressional approval for the project Colonel Leslie Groves was responsible for overseeing the project for the U.S. Ground was broken on 11 September 1941, and the building was dedicated on 15 January 1943. The building was designed by American architect George Bergstrom and built by contractor John McShain. military, the phrase The Pentagon is often used as a metonym for the Department of Defense and its leadership. It was constructed on an accelerated schedule during World War II. The Pentagon is the headquarters building of the United States Department of Defense, in Arlington County, Virginia, across the Potomac River from Washington, D.C.
