The day on which al-Qaeda terrorists struck at New York and Washington, killing over 3000 people. Four airliners were hijacked shortly after take-off by 19 suicidal terrorists: two were flown into the twin towers of New York’s World Trade Center causing their collapse, one was crashed into the Pentagon in Washington, and one hit the ground near Pittsburgh, presumably after a struggle between the passengers and the hijackers. The outrage led the USA to launch its war on terrorism.