Pentagon History
World's largest office building has distinctive past By David Johnson The world's largest office building, the Pentagon is synonymous with the Department of Defense and a symbol of American military might. Exactly 60 years before the September 2001 attacks, on September 11, 1941, ground was broken in Arlington Country, Virginia, for a huge new building to house the War Department, forerunner of today's Department of Defense. The department was then operating from 17 separate buildings in Washington . Pearl Harbor Alters Plans At certain periods 13,000 people worked on the project. Originally, plans called for three floors, but as the military prepared for war after the attack on Pearl Harbor , two more floors were added. To conserve steel, concrete ramps were used in place of elevators and the outside walls were made of reinforced concrete. The Pentagon was built in "stripped classical" style, a variation of Greek and Roman clas...