History of the United States (1991–2008) South Tower less than twenty minutes later at 9:03 A.M. (EST), resulting in the collapse of both 110 story skyscrapers, and the destruction of the World Trade Center. The third hijacked plane, American Airlines Flight 77, was crashed into the Pentagon (the headquarters of the United States Department of Defense) in Arlington County, Virginia, demolishing a section of the outer southwest facing wall. After discovering that their plane, United Airlines Flight 93, was going to be used as a missile, passengers attempted to regain control of the plane which had been redirected towards Washington, D.C. However, after regaining control from
Department of the East the 1916 Defense Act. It was replaced by the Second Corps Area. The headquarters of the 1853–1861 Department of the East in 1861 was Troy, New York, except for the few years under the command of Gen. Bankhead, when he made his headquarters at Ft. McHenry, in Baltimore, MD. The headquarters of the last Department of the East was originally located in leased office space in New York City until 1878, when the War Department relocated all headquarters functions across the country to army posts due to economic considerations. The headquarters was relocated to Fort Columbus, renamed Fort Jay in