It has a total floor area of 6,500,000 sq ft (604,000 m). Offices are 3,700,000 sq ft (344,000 m). Approximately 25,000 military and civilian employees work in The Pentagon. It has five sides, five floors above ground, two basement levels, and five ring corridors per floor with a total of of corridors. The Pentagon includes a five-acre (20,000 m) central plaza, which is shaped like a pentagon.