The term "9/11" refers to the terrorist attacks that occurred on the morning of September 11, 2001. On that day, 19 terrorists from the Islamist extremist group al-Qaeda hijacked four commercial airplanes in the United States. Two planes were flown into the Twin Towers of the World Trade Center in New York City, causing both towers to collapse. A third plane was crashed into the Pentagon near Washington, D.C., and the fourth plane crashed into a field in Pennsylvania after passengers attempted to overcome the hijackers
. These coordinated suicide attacks killed 2,977 people, including civilians, firefighters, law enforcement officers, military personnel, and the hijackers themselves, making it the deadliest terrorist attack in history. The attacks resulted in massive destruction and loss of life, and prompted the United States to launch the global War on Terror, including military actions in Afghanistan and Iraq
. The events of 9/11 had profound and lasting effects on the U.S. and the world, leading to changes in security policies, international relations, and ongoing conflicts
. The National September 11 Memorial & Museum in New York City commemorates the victims and educates the public about the attacks and their impact
