what happen on 9/11

On September 11, 2001, a series of coordinated terrorist suicide attacks were carried out by the Islamist extremist group al-Qaeda against the United States. Nineteen terrorists hijacked four commercial airplanes. Two planes were flown into the Twin Towers of the World Trade Center in New York City, causing both towers to collapse within hours. A third plane crashed into the Pentagon, the headquarters of the U.S. Department of Defense in Arlington, Virginia. The fourth plane crashed into a field in Pennsylvania after passengers attempted to retake control from the hijackers; it is believed this plane's intended target was either the U.S. Capitol or the White House. The attacks resulted in the deaths of 2,977 people, making it the deadliest terrorist attack in history. These events led to the U.S. launching a global war on terror