On September 11 , 2001 , Islamist terrorists hijacked American Airlines Flight 11 and crashed it into the northern façade of the North Tower at 8:46:40 a.m. ; the aircraft struck between the 93rd and 99th floors . Seventeen minutes later , at 9:03:11 a.m. , a second group crashed the similarly hijacked United Airlines Flight 175 into the southern façade of the South Tower , striking it between the 77th and 85th floors . The damage caused to the North Tower by Flight 11 destroyed any means of escape from above the impact zone , trapping 1,344 people . Flight 175 had a much more off-centered impact compared to Flight 11 , and a single stairwell was left intact ; however , only a few people managed to descend successfully before the tower collapsed . Although the South Tower was struck lower than the North Tower , thus affecting more floors , a smaller number , fewer than 700 , were killed instantly or trapped
American Airlines Flight 11
American Airlines Flight 11
World Trade Center (1973–2001)