of 17.5 mi of corridors, with a central 5 acre pentagonal plaza. About 23,000 military and civilian employees work in the Pentagon, as well as about 3,000 non-defense support personnel.

In 2001, the Pentagon was damaged during the September 11 attacks. Five Al-Qaeda hijackers flew American Airlines Flight 77 into the western side of the building, killing themselves and 184 other people, including 59 on the