On September 11, 2001, at around eight o'clock in the morning eastern daylight time, four passenger planes took off from various East Coast cities in the United States bound for destinations on the West Coast. Within an hour, all four had been taken over by hijackers and transformed into flying bombs, targeted at seats of American financial and governmental power. United Airlines flight 175, a Boeing 767 with 56 passengers and 9 crew, departed Boston's Logan Airport at 7.58 AM; one minute later, American Airlines flight 11, also a Boeing 767, carrying 81 passengers and 11 crew, left the same airport. Both planes were bound for Los Angeles. At 8.45 AM, American Airlines flight 11 crashed into the north tower of the World Trade Center in lower Manhattan, to be followed 21 minutes later by United Airlines flight 175, which flew into the south tower. A third plane, American Airlines flight 77, a Boeing 757 carrying 58 passengers and 6 crew, departed Washington's Dulles airport at 8:10 AM, flew some distance toward its destination of Los Angeles, reversed course, and at 9.40 AM crashed into the Pentagon building in Washington, DC, headquarters of the United States Defense Department. A fourth plane, United Airlines 93, another Boeing 757 with 38 passengers and 7 crew aboard, left Newark, New Jersey, at 8:01 AM bound for San Francisco. After flying westward as far as Cleveland, it turned eastward and, at 10:37 AM, crashed into open ground in rural Pennsylvania some 80 miles southeast of Pittsburgh. It is assumed that this plane's intended target was another prominent building in Washington, possibly the White House or the Capitol building.
It quickly emerged that passengers on some of the flights had been in contact by mobile phone with relatives in the minutes before impact, giving some insight into the methods, if not as yet the motives, of the hijackers. In some cases, passengers were told by the hijackers to contact relatives; in other cases, passengers locked themselves in toilet compartments and made frantic calls to