Series of airline hijackings and suicide bombings against U.S. targets perpetrated by 19 militants associated with the Islamic extremist group al-Qaeda. The attacks were planned well in advance; the militants—most of whom were from Saudi Arabia—traveled to the U.S. beforehand, where a number received commercial flight training. Working in small groups, the hijackers boarded 4 domestic airliners in groups of 5 (a 20th participant was alleged) on Sept. 11, 2001, and took control of the planes soon after takeoff. At 8:46 AM (local time), the terrorists piloted the first plane into the north tower of the World Trade Center in New York City. A second plane struck the south tower some 15 minutes later. Both structures erupted in flames and, badly damaged, soon collapsed. A third plane struck the southwest side of the Pentagon near Washington, D.C., at 9:40, and within the next hour the fourth crashed in Pennsylvania after its passengers—aware of events via cellular telephone—attempted to overpower their assailants. Some 2,750 people were killed in New York, 184 at the Pentagon, and 40 in Pennsylvania. All 19 terrorists died.
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Only 14 people escaped from the impact zone of the South Tower after it was hit, and only four people from the floors above it. They escaped via Stairwell A, the only stairwell which had been left intact after the impact. No one was able to escape from above the impact zone in the North Tower after it was hit, as all stairwells and elevator shafts on those floors were destroyed. But a small group of people did survive the collapse in the top of the North Tower. After the collapse of the towers, only 23 survivors who were in or below the towers escaped from the debris, including 15 rescue workers. The last survivor was pulled from the rubble 27 hours after the collapse of the towers. A total of 6,294 people were reported to have been treated in area hospitals for injuries related to the 9/11 attacks in New York City. There were (excluding the hijackers) 3,001 fatalities.