On September 11, 2001, a series of coordinated terrorist attacks were carried out by the Islamist extremist group al-Qaeda against the United States. Four commercial airliners were hijacked, with two flown into the Twin Towers of the World Trade Center in New York City and one into the Pentagon in Arlington, Virginia. The fourth plane, United Airlines Flight 93, crashed into a field in Pennsylvania after passengers attempted to retake control. The attacks resulted in nearly 3,000 deaths and had profound impacts on global politics, leading to the War on Terror and significant changes in U.S. foreign and domestic policies.