September 11 attacks

The September 11 attacks, commonly called 9/11, were a series of coordinated terrorist attacks in the United States on September 11, 2001.

The September 11 attacks, commonly called 9/11, were a series of coordinated terrorist attacks in the United States on September 11, 2001. Nineteen al-Qaeda hijackers took control of four commercial airliners, crashing two into the World Trade Center, one into the Pentagon, and one into a field in Pennsylvania after passengers intervened. The attacks killed 2,977 victims, not including the hijackers, and led to major changes in aviation security, U.S. foreign policy, and global counterterrorism efforts.

Background

Al-Qaeda, an Islamist extremist organization, planned and carried out the attacks using hijacked commercial airliners. The operation targeted symbolic and strategic sites in New York City and Washington, D.C.

The attacks

The hijackers took control of four flights and used them as weapons against the World Trade Center and the Pentagon. Flight 93 crashed in Pennsylvania after passengers resisted the hijackers.

Casualties and damage

The attacks killed 2,977 victims, including passengers, office workers, first responders, military personnel, and people on the ground. They also destroyed the Twin Towers and caused extensive damage in New York City and at the Pentagon.

Global impact

9/11 led to sweeping changes in airport security, counterterrorism policy, intelligence operations, and international relations. It also shaped public memory through annual observances, museums, and memorials.

Memorials

The main memorial, the National September 11 Memorial & Museum, is located at the former World Trade Center site in Lower Manhattan. Other memorials and remembrance sites exist in New York, Virginia, and Pennsylvania.