In 1941 the War Department began building their headquarters, known as the Pentagon, in Arlington. The Pentagon was one of the first federal buildings constructed outside of downtown Washington. The Pentagon's 3.6 million square feet of office space took just over a year to complete at a cost of $75 million.
The unique pentagon shape of the building was chosen so that the building could fit between Arlington Memorial Drive, Arlington Memorial Bridge, National Cemetery, Arlington Ridge Road, and Fort Myer. Though this location was deemed unsuitable for the building, the pentagonal shape remained. The Pentagon's construction led to the destruction of the nearby Queen City African American community.