In the United States on September 11, 2001 (9/11), 19 terrorists from al-Qaeda hijacked four airplanes in an attempt to crash them into American landmarks. American Airlines Flight 11 and United Airlines Flight 175 crashed into the World Trade Center, and American Airlines Flight 77 was crashed into the Pentagon. United Airlines Flight 93 was intended to be crashed into the U.S. Capitol or White House, but the hijackers intentionally crashed it into a field in Pennsylvania instead, due to a passenger revolt.