AP US History
The 9/11 terrorist attacks refer to a series of coordinated suicide attacks carried out by the extremist group al-Qaeda on September 11, 2001, targeting key locations in the United States. The most notable events of that day involved the hijacking of four commercial airliners, two of which were flown into the Twin Towers of the World Trade Center in New York City, while another struck the Pentagon in Arlington, Virginia, and the fourth crashed in Pennsylvania. This devastating event significantly impacted global security, U.S. foreign policy, and the perception of terrorism in the 21st century.