September 11, 2001 Attacks

On the morning of September 11, 2001, members of the al-Qaeda terrorist network hijacked four U.S. commercial airliners in a coordinated attack. Two of the aircraft were deliberately flown into the twin towers of the World Trade Center in New York City, causing both skyscrapers to collapse and killing thousands of people.

A third hijacked airliner was crashed into the Pentagon outside Washington, D.C., the headquarters of the U.S. Department of Defense. The fourth aircraft, believed to be headed for another target in the Washington area, crashed into a field near Shanksville, Pennsylvania, after passengers fought back against the hijackers, preventing it from reaching its intended destination.

The attacks were the deadliest act of terrorism in U.S. history and transformed the role of aviation in American life. They led to sweeping changes in airport and airline security, the creation of new federal agencies, and the launch of the broader campaign that became known as the War on Terror.