Twin Towers was attactes on September 11, 2001

The September 11 attacks (often referred to as September 11th or 9/11) were a series of coordinated suicide attacks by al-Qaeda upon the United States on September 11, 2001. On that morning, 19 al-Qaeda terrorists hijacked four commercial passenger jet airliners. The hijackers intentionally crashed two of the airliners into the Twin Towers of the World Trade Center in New York City, killing everyone on board and many others working in the buildings. Both buildings collapsed within two hours, destroying nearby buildings and damaging others. The hijackers crashed a third airliner into the Pentagon in Arlington, Virginia, just outside Washington, D.C. The fourth plane crashed into a field near Shanksville in rural Pennsylvania after some of its passengers and flight crew attempted to retake control of the plane, which the hijackers had redirected toward Washington, D.C. There were no survivors from any of the flights.When New York City's giant World Trade Center towers plunged to earth following successive suicide terrorist attacks on September 11th, the world was confronted with one of most shocking—and sickening—sights of modern times. The mechanisms by which these huge and seemingly solid edifices suddenly collapsed, snuffing out the lives of thousands, was the subject of a preliminary postmortem conducted last week in Cambridge, Mass. A panel of Boston area-based civil and structural engineers convened to discuss the fate of the superskyscrapers, struck by hijacked passenger planes, in front of an overflow audience on the campus of the Massachusetts Institute of Technology. Their starkly sobering analyses highlighted the vulnerabilities of ultra-tall buildings to fire and pointed out steps that could be taken to lessen them. On the morning of September 11, 2001, terrorists from al-Qaeda hijacked four planes. Two were Boston-to-Los Angeles flights, which the hijackers diverted to New York City. At 8:45 a.m., American Airlines Flight 11 was flown into the north tower of the World Trade Center. Eighteen minutes later, United Airlines Flight 175 was flown into the south tower. Each plane was loaded with sufficient jet fuel for its intended cross-country trip, which ignited upon impact, creating intense fireballs in both towers and weakening the structural integrity of each. At 9:50 a.m., the affected floors of the south tower gave way; the upper floors collapsed onto the lower ones, destroying the tower and crushing everyone who was still inside it. At 10:29 a.m., the same happened to the north tower. 2,824 people were killed in the attacks, including hundreds of firefighters and other rescue workers.