History: Collapse Of The World Trade Center, September 11, 2001, Lower Manhattan, New York City, United States

Destruction
On September 11, 2001, terrorists hijacked American Airlines Flight 11 and crashed it into the northern façade of the north tower at 8:46 a.m., the aircraft striking between the 93rd and 99th floors. Seventeen minutes later, at 9:03 a.m., a second team of terrorists crashed the similarly hijacked United Airlines Flight 175 into 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 pass through it 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. At 9:59 a.m., the South Tower collapsed after burning for approximately 56 minutes. The fire caused steel structural elements, already weakened from the plane impact, to fail. The north tower collapsed at 10:28 a.m., after burning for approximately 102 minutes.
At 5:20 p.m. on September 11, 2001, 7 World Trade Center started to collapse with the crumble of the east penthouse, and it collapsed completely at 5:21 p.m. owing to uncontrolled fires causing structural failure. 3 World Trade Center, a Marriott hotel, was destroyed during the collapse of the two towers. The three remaining buildings in the WTC plaza sustained heavy damage from debris and were ultimately demolished. The Deutsche Bank Building across Liberty Street from the World Trade Center complex was later condemned owing to the uninhabitable toxic conditions inside; it was deconstructed, with work completed in early 2011. The Borough of Manhattan Community College's Fiterman Hall at 30 West Broadway was also condemned owing to extensive damage in the attacks and is slated for deconstruction.