The September 11 Attacks were a series of coordinated terrorist attacks carried out by the extremist group Al-Qaeda on September 11, 2001. Four commercial airliners were hijacked, with two crashing into the World Trade Center towers in New York City, one into the Pentagon in Arlington, Virginia, and the fourth, United Airlines Flight 93, crashing in Pennsylvania after passengers attempted to regain control. These attacks resulted in the deaths of nearly 3,000 people and caused significant destruction, leading to widespread changes in U.S. and global security policies. The events of that day have had a lasting impact on international relations and the fight against terrorism.