Together with a simultaneous attack on the Pentagon in Arlington , Virginia , and a failed plane hijacking that resulted in a plane crash in Shanksville , Pennsylvania , the attacks resulted in the deaths of 2,996 people ( 2,507 civilians , 343 firefighters , 72 law enforcement officers , 55 military personnel , and the 19 hijackers ) . More than 90 % of the workers and visitors who died in the towers had been at or above the points of impact . In the North Tower , 1,355 people at or above the point of impact were trapped , and died of smoke inhalation , fell , jumped from the tower to escape the smoke and flames , or were killed when the building eventually collapsed . One stairwell in the South Tower , Stairwell A , somehow avoided complete destruction , unlike the rest of the building . When Flight 11 hit , all three staircases in the North Tower above the impact zone were destroyed , thus making it impossible for anyone above the impact zone to escape . 107 people below the point of impact also died
a simultaneous attack
American Airlines Flight 77
One World Trade Center