Department of Defense

The Department of Defense is America's oldest and largest government agency. With our military tracing its roots back to pre-Revolutionary times, the Department of Defense has grown and evolved with our nation. Headquarters of the Department of Defense, the Pentagon is one of the world's largest office buildings. It is twice the size of the Merchandise Mart in Chicago, and has three times the floor space of the Empire State Building in New York. Built during the early years of World War II, it is still thought of as one of the most efficient office buildings in the world. Despite 17.5 miles of corridors it takes only seven minutes to walk between any two points in the building. The national security depends on our defense installations and facilities being in the right place, at the right time, with the right qualities and capacities to protect our national resources. Those resources have never been more important as America fights terrorists who plan and carry out attacks on our facilities and our people. Our military servicemembers and civilians operate in every time zone and in every climate. More than 450,000 employees are overseas, both afloat and ashore. http://www.defense.gov/about/