The Pentagon

Symbol of military power.

One of the largest office buildings in the world. It is about 6.5 million square feet (150 acres; 60 ha) of floor space, of which 3.7 million sq ft (85 acres; 34 ha) are used as offices.

It has five sides, five storeys above ground, two levels below ground, and five ring corridors per floor, creating a total of 17.5 miles (28.2 km) of corridors. It has a height of 23 m (77 ft), and each of the five sides is 281 m (921 ft) long.

The whole complex includes: the main building, numerous parking lots, 30 miles of streets and 21 bridges.

It was designed by American architect George Bergstrom and built by contractor John McShain. The land the Pentagon was first planned to go on was bordered on five sides by roads, so the architects designed a five-sided building.

Construction began on 11 September 1941, was completed in approximately 16 months, and dedicated on 15 January 1943.

It take underwent a major renovation, beginning in 1998.

In the secretary of defense room there is the largest desk in the Pentagon, on the desk there are three telephones, white - with a direct connection to the White House, red - for talks with Russia and commando staging places, blue - to communicate with the most important people in the building.

On the 60th anniversary of the building's construction beginning - 11.09.2001, during the September 11 attacks, a hijacked airliner was flown into the western side of the Pentagon, killing 189 people (five al-Qaeda hijackers, 59 on the airplane and 125 in the Pentagon).