Go to: September 11, 2001 Suicide hijackers commandeer four U.S. commercial flights in order to crash them into American landmarks. They crash two jumbo jets into the World Trade Center in New York and one into the Pentagon in Washington. The fourth attempt fails after passengers learn of the other flights and rush the hijackers. The incident ends when the plane, headed toward Washington, crashes into a field in Pennsylvania. The impact and fire at the World Trade Center cause the towers to collapse. By day's end, nearly 3,000 people have been killed.