On Sept. 11, 2001, 19 terrorists purposely crashed four planes into various buildings in the United States including the top floors of the North and South Twin Towers and the World Trade Center in New York City and the Pentagon in Washington D.C. This graphic shows the minute by minute timeline of the attacks on 9/11 to commemorate the first responders and servicemen and women who made the ultimate sacrifice on this day 22 years ago, as well as all innocent victims who lost their lives.