The Pentagon _History Channel_

The Pentagon--the name alone conjures up an imposing image of American power. Completed in 1943 this five-sided nerve center for the nation's armed services is the largest office building in the world--yet it takes only seven minutes to walk between any two points in the building because of its unique shape. Walk along its more than 17 miles of corridors with the 24000 men and women who work here each day. Updated to reflect the September 11 2001 terrorist attack.