Al-Qaeda launched terrorist attacks in the United States on September 11, 2001. Coordinated by 19 militants, the attacks involved hijacking four commercial airplanes, with two crashing into the Twin Towers of the World Trade Center in New York City and another into the Pentagon in Arlington, Virginia. The fourth plane, United Airlines Flight 93, crashed in Pennsylvania after passengers attempted to regain control. This unprecedented act of terrorism resulted in nearly 3,000 deaths and had profound effects on U.S. foreign and domestic policy, leading to the War on Terror, increased national security measures, and significant geopolitical changes worldwide.