Building introduction: The Pentagon is named after its regular pentagon shape. The Pentagon was completed on April 15, 1943. It covers an area of ​​2.359 million square meters and has a total construction area of ​​608,000 square meters. The building is 22 meters high and has 6 floors. It can accommodate 23,000 staff (including military and civilian personnel). Office. The building has complete facilities, including 4,200 clocks of various kinds, 691 drinking fountains, 284 washrooms, 16,250 electric lights of various kinds, restaurants, shops, post offices, banks, bookstores and other service facilities; there are 4 large rooms outside the building. The parking lot can accommodate about 10,000 cars. In addition, the Pentagon contains a five-acre (20,000 square meters) central plaza in the shape of a pentagon, informally known as "Zero Ground."