On September 11, 2001, 19 militants associated with Al Qaeda hijacked four aeroplanes and carried out suicide attacks in the United States. A total of 2,996 people were killed during the 9/11 terrorist attacks. Two planes were flown into the Twin Towers of the World Trade Center in New York City, a third plane hit the Pentagon just outside Washington, D.C., and the fourth plane crashed in a field in Shanksville, Pennsylvania. Even after 18 years, 9/11 remains the most dreadful act of terrorism the world has witnessed.