The September 11 attacks were a series of coordinated terrorist attacks that occurred on September 11, 2001, in the United States. Four commercial airplanes were hijacked by members of the extremist group al-Qaeda. Two planes were flown into the World Trade Center towers in New York City, causing their collapse, while a third plane struck the Pentagon in Arlington, Virginia. The fourth plane, United Airlines Flight 93, crashed into a field in Pennsylvania after passengers attempted to regain control from the hijackers. These attacks resulted in the deaths of nearly 3,000 people and caused significant destruction. In response, the U.S. government launched the War on Terror, leading to military operations in Afghanistan to dismantle al-Qaeda and remove the Taliban from power. The events of September 11 have had a lasting impact on global security policies and international relations.