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

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.
In the immediate aftermath of the attacks, media reports suggested that tens of thousands might have been killed in the attacks, as on any given day over 50,000 people could be inside the towers. Ultimately, 2,753 death certificates (excluding those for hijackers) were filed relating to the 9/11 attacks, including one filed for Felicia Dunn-Jones, who was added to the official death toll in May 2007; Dunn-Jones died five months later from a lung condition linked to exposure to dust during the collapse of the World Trade Center. Three other victims were then added to the official death toll by the city medical examiner's office: Dr. Sneha Anne Philip, who was last seen the day before the attacks; Leon Heyward, a man who developed lymphoma and subsequently died in 2008 as a result of dust ingestion during the events following the attacks to the Twin Towers; and Jerry Borg, who died in December 2010 of pulmonary sarcoidosis determined in June 2011 to be the result of dust from the attacks. Cantor Fitzgerald L.P., an investment bank on the 101st–105th floors of One World Trade Center, lost 658 employees, considerably more than any other employer, while Marsh & McLennan Companies, located immediately below Cantor Fitzgerald on floors 93–101 (the location of Flight 11's impact), lost 295 employees, and 175 employees of Aon Corporation were killed. In addition, 343 of the dead were New York City firefighters, 84 were Port Authority employees, of whom 37 were members of the Port Authority Police Department, and another 23 were New York City Police Department officers. Ten years after the attacks, only 1,629 victims have been positively identified. Of all the people who were still in the towers when they collapsed, only 20 were pulled out alive. PAPD Officers William Jimeno and Sgt. John McLoughlin were survivors 18 and 19.