The most destructive attack of terrorism ever launched against the United States. On September 11, 2001, a group of Islamic terrorists, widely believed to be part of the Al Qaeda network, hijacked three commercial airliners in midair, took over the controls, and deliberately crashed them into the Pentagon and the twin towers of the World Trade Center (WTC). A total of 189 people who worked at the Pentagon, which suffered severe damage, were killed, and another sixty-four died on the airliner. Fire caused by the initial crash into the WTC led to the collapse of each tower, but not before hundreds of New York City firefighters and police had entered the towers to rescue victims. When the towers collapsed, many of them were killed, along with thousands of workers who had been trapped after the initial crashes on the towers' upper floors.
Counting firefighters, police, tower workers, and passengers on the doomed airliners, the death toll at the WTC ran to over three thousand people. Another forty-four people died on a fourth hijacked airliner, which crashed in a field near Pittsburgh. The attacks provoked outrage not only in the United States, but also abroad, both because of their savagery and because roughly ten percent of those killed in the collapse of the twin towers were foreign nationals.
In response, President George W. Bush assembled an international coalition against terrorism. He received strong support from America's traditional European allies — NATO, for example, officially declared the attacks an assault against all of its members — and from the Russian Federation, which had been battling Islamic separatists in Chechnya. Even China, which feared Islamic separatist movements in its far western provinces, gave verbal support to the campaign against terrorism. The Islamic world, in contrast, was much cooler. Nevertheless, Bush was able to secure from Pakistan's government the right to use Pakistan as a base from which to attack Afghanistan, whose Taliban, it was believed, harbored Al Qaeda members and Osama bin Laden. American air strikes against the Taliban commenced three weeks after the September 11 attacks.
Note: In addition to the human carnage, the attacks severely crippled both the U.S. and foreign economies. For example, in the wake of the attacks, air travel plummeted and insurance companies faced enormous costs for the damage.
Note: Many Americans compared the attacks to Pearl Harbor, because they took an unprepared America by surprise.