The September 11 attacks involved 19 al-Qaeda terrorists hijacking 4 commercial airplanes and crashing them into important buildings, killing nearly 3,000 people. On September 11, 2001, the terrorists crashed two planes into the World Trade Center in New York City, one into the Pentagon near Washington D.C., and a fourth plane crashed in Pennsylvania after passengers fought the hijackers. The attacks were orchestrated by Osama bin Laden and al-Qaeda to attack the United States.