September 11, 2001

On September 11, 2001, terrorists hijacked four airplanes; two crashed into the Twin Towers of the World Trade Center in New York City, causing their collapse. A third plane hit the Pentagon in Virginia, damaging a key U.S. military building. The fourth plane, United Flight 93, was headed for Washington but crashed into a field in Pennsylvania after passengers tried to overcome the hijackers. The attacks resulted in nearly 3,000 deaths and prompted global security changes, especially in air travel and counterterrorism policies. It marked a major turning point in U.S. and world history regarding terrorism and security.