On September 11, 2001, four commercial airliners were hijacked by al-Qaeda terrorists. Two planes crashed into the World Trade Center towers in New York City, a third hit the Pentagon just outside Washington D.C., and a fourth crashed in a field in Pennsylvania. Nearly 3,000 people lost their lives in the attacks that had major short and long term impacts on the United States. The document provides details on the events of 9/11 including the locations that were attacked, the numbers of casualties, and broader effects in the aftermath such as economic impacts and mental health issues.