Pentagon

This American military headquarters provides workspace for 23,000 employees, making it the world's largest office building. The five sectors of the building are connected by 17.5 miles of diagonal corridors, with 19 escalators, 4200 clocks, and over 100,000 miles of telephone cable. Inside, there are also two banks, several restaurants and snack bars, a post office, an Amtrak ticket office, beauty salon and a dry cleaner. Tours are only available for schools and other educational organizations and must be scheduled several months in advance. Tours are available for the general public; contact their state representative's office for reservations. METRO: Pentagon