World's Largest Office Building

The Pentagon is the world’s largest office building by floor area, with about 6,500,000 sq ft (604,000 m²), of which 3,700,000 sq ft (344,000 m²) are used as offices. Approximately 23,000 military and civilian employees and about 3,000 non-defense support personnel work in the Pentagon.

        

The Pentagon

It has five sides, five floors above ground (plus two basement levels), and five ring corridors per floor with a total of 17.5 mi (28.2 km) of corridors. The Pentagon includes a five-acre (20,000 m²) central plaza, which is shaped like a pentagon and informally known as “ground zero”, a nickname originating during the Cold War and based on the presumption that the Soviet Union would target one or more nuclear missiles at this central location in the outbreak of a nuclear war.