Terrorist attacks in the US

When the first airplane flies into the northern tower of the World Trade Center, many regard it at first as a tragic accident. But then a second passenger plane crashes into the southern tower. By this time reports begin circulating about the hijacking of a third and fourth airplane. Rescue services are able to evacuate thousands of people before the towers in downtown New York City collapse.

It quickly becomes clear: the United States is under attack by terrorists belonging to the international organization al Qaida, led by Osama bin Laden. Some 3,000 people die in the attacks on September 11, 2001. Washington vows to wage a "War on Terror" and for the first time ever NATO invokes Article V, the mutual defence article which declares an attack on one of its members is an attack on all.