I have always been interested in the Pentagon. Not only from the building itself but just what goes on inside it. Needless to say I have never visited it, let alone been inside. The Pentagon oozes authority, secrecy and power. This hub has more about the Pentagon.

The Pentagon is the headquarters of the United States Department of Defense, located in Arlington, Virginia. As a symbol of the U.S. military, "the Pentagon" is often used metonymically to refer to the Department of Defense rather than the building itself.

Designed by architect George Bergstrom (1876 - 1955) and built by Philadelphia, Pennsylvania general contractor John McShain, the building was dedicated on January 15, 1943. It is the highest-capacity office building in the world and the third largest building in the world by floor area. It houses approximately 23,000 military and civilian employees and about 3,000 non-defense support personnel. It has five sides, five floors above ground (plus two basement levels), and five ring corridors per floor with a total of 17.5 miles (28.2 kilometers) of corridors.

At five acres (20,000 m²), the central plaza in the Pentagon is the world's largest "no-salute, no-cover" area (an area exempt from the normal rule that, when out of doors, U.S. military personnel must wear hats and salute superior officers). The open space in the center is 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. At the center of this plaza is the "Ground Zero Cafe," a snack bar. At one point, a target was painted on the ground as a bit of gallows humor, but after the September 11, 2001 terrorist attacks, it was painted over.

Just south of the Pentagon are Pentagon City and Crystal City, extensive shopping and high-density residential districts in Arlington. Arlington National Cemetery is to the north. The Washington Metro Pentagon station is also located at the Pentagon, on the Blue and Yellow Lines. The Pentagon is surrounded by the complex Pentagon road network. The Pentagon has between 700 and 800 bases around the world, in 63 countries.