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
Arlington County, Virginia Arlington County, Virginia Arlington County is a county in the Commonwealth of Virginia, often referred to simply as Arlington or Arlington, Virginia. In 2016, the county's population was estimated at 230,050, making it the sixth-largest county in Virginia, or the fourth-largest city if it were incorporated as such. It is the 5th highest-income county in the U.S. by median family income, and has the highest concentration of singles in the region. The county is coterminous with the U.S. Census Bureau's census-designated place of Arlington. Though a county, it is also treated as the second-largest principal city of the Washington metropolitan