Ten-Nine-Eleven

September 11, 2001, often called 9/11, was a terrorist attack in which al-Qaeda extremists hijacked four commercial airplanes. They intentionally crashed two planes into the Twin Towers of the World Trade Center in New York City, causing both buildings to collapse. A third plane hit the Pentagon near Washington, D.C., and the fourth, United Airlines Flight 93, crashed into a field in Pennsylvania after passengers tried to overpower the hijackers. The attacks resulted in nearly 3,000 deaths, profoundly affecting U.S. security policies, leading to the War on Terror, and prompting global efforts to combat terrorism.