September 11, 2001 is a date that most Americans will never forget. Most have vivid memories of where they were and what they were doing when they learned of the terrorists’ attacks involving commercial airlines in New York, Washington, D.C., and Pennsylvania. On that date 21 years ago, over 3,000 people lost their lives in the attacks, including many first responders, in attacks on the World Trade Center Towers, the Pentagon, and United Flight 93 by hijacking the airplanes.