Art Hill in Forest Park, St Louis, Missouri has a 10th anniversary of 911 with a display of 3000 American Flags. The September 11 attacks (called September 11, September 11th or 9/11), were a series of four coordinated suicide attacks upon the United States in New York City and the Washington, D.C. area on September 11, 2001. On that morning, 19 terrorists from the Islamist militant group al-Qaeda hijacked four passenger jets. The hijackers intentionally crashed two planes into the Twin Towers of the World Trade Center in New York City; both towers collapsed within two hours. Hijackers crashed a third plane into the Pentagon in Arlington, Virginia. A fourth jet, United Airlines Flight 93, crashed into a field near Shanksville, Pennsylvania before it could reach its intended target in Washington, D.C. after the passengers attempted to take control. Nearly 3,000 died in the attacks.