9/11 Attacks

The 9/11 attacks, occurring on September 11, 2001, involved coordinated terrorist acts by the extremist group al-Qaeda. Nineteen hijackers took control of four commercial airplanes, crashing two into the World Trade Center towers in New York City, leading to their collapse. A third plane hit the Pentagon, and the fourth, United Airlines Flight 93, crashed in Pennsylvania after passengers attempted to regain control. Nearly 3,000 people died, making it the deadliest terrorist attack in U.S. history. The attacks prompted significant changes in U.S. foreign policy and led to the War on Terror, including military actions in Afghanistan.