On September 11, 2001, a tragic historical event known as the 9/11 attacks occurred in the United States. Coordinated terrorist attacks by the extremist group al-Qaeda targeted key landmarks, including the World Trade Center in New York City and the Pentagon in Arlington, Virginia. Two commercial airliners were flown into the Twin Towers, causing their eventual collapse, while a third plane crashed into the Pentagon. A fourth plane, United Airlines Flight 93, was hijacked but ultimately crash-landed in Pennsylvania after passengers intervened. The attacks resulted in nearly 3,000 deaths and had profound global political and social repercussions.