The 9/11 attacks occurred at four main locations in the United States on September 11, 2001:

• Two hijacked planes were flown into the Twin Towers of the World Trade Center in New York City, causing their collapse and killing thousands

• A third plane crashed into the Pentagon, the U.S. Department of Defense headquarters, in Arlington County, Virginia

• The fourth hijacked plane, United Airlines Flight 93, crashed into a rural field near Shanksville in Somerset County, Pennsylvania, after passengers attempted to regain control from the hijackers

These coordinated terrorist attacks killed nearly 3,000 people and were the deadliest terrorist attacks in history