The Washington area was a main target of the September 11, 2001 attacks. American Airlines Flight 77 was hijacked by five Islamic terrorists and flew into the Pentagon in Arlington County, just across the Potomac River from Washington, killing 125 people inside the building, as well as 64 on board the airliner, including the five terrorists. United Airlines Flight 93, which was also hijacked and which went down in an open field near Shanksville, Pennsylvania, supposedly intended to target either the White House or the United States Capitol Building.