2,996: The deadliest aviation-related disaster of any kind, regarding fatalities on both the aircraft and the ground, was the destruction of the World Trade Center in New York City on September 11, 2001. On that morning, four commercial jet airliners traveling on transcontinental flights from East Coast airports to California were hijacked after takeoff. The four hijacked aircraft were subsequently crashed in four coordinated suicide attacks against major American landmarks by 19 Islamic terrorists affiliated with Al-Qaeda. American Airlines Flight 11 and United Airlines Flight 175 were intentionally crashed into the North and South Towers of the World Trade Center, respectively, destroying both buildings in less than two hours. The World Trade Center crashes killed 2,753, the vast majority of fatalities being occupants of the two towers or emergency personnel responding to the disaster. In addition, 184 were killed by the impact of American Airlines Flight 77, which crashed into the Pentagon in Arlington, Virginia, causing severe damage and partial destruction to the building's west side. The impact of United Airlines Flight 93 into a field in Somerset County, Pennsylvania, killed all 40 passengers and crew aboard the aircraft, after the flight's passengers fought back and prevented the hijackers from reaching their designated target. This brought the total number of casualties of the September 11 attacks to 2,996 (including the 19 terrorist hijackers). As deliberate terrorist acts, the 9/11 crashes were not classified as accidents, but as mass-killing. The events were treated by the United States and the member nations of NATO as an act of war and terrorism. The War on terror was subsequently launched by the United States and NATO in response to the attacks.