In 1941, with World War II raging in Europe, the United States made plans to consolidate personnel in its War Department, which had 24,000 employees working out of 17 different buildings around the District of Columbia. Lt. Col. Hugh Casey was tasked with designing a building that would fit on a five-sided parcel of land near Arlington National Cemetery, and house a staff of 40,000. Architects came up with a pentagonal plan that would fit the site perfectly. Each of the five wedges of the 29-acre structure would feature concentric rings of office space, linked by 17.5 miles (28 km) of corridors, with a courtyard in the center. Officials ultimately decided to construct the building on a different site in Northern Virginia, but they kept the Pentagon’s unique shape.
An office building like no other: