The September attacks were a series of four suicide attacks that were committed in the United States on September 11, 2001, coordinated to strike the areas of New York City and Washington, D.C. On that Tuesday morning, 19 terrorists from the Islamist militant group al-Qaeda hijacked four passenger jets. The hijackers intentionally piloted two of those planes, American Airlines Flight 11 and United Airlines Flight 175, into the North and South towers of the World Trade Center complex in New York City; both towers collapsed within two hours.