On this day in history, September 11, 2001, US experiences the worst terrorist attack in American history

On this tragic day in history, Sept. 11, 2001, Americans and the entire world watched as two airplanes slammed into the World Trade Center’s Twin Towers in New York City while a third plane crashed into the Pentagon in Arlington, Virginia.
 
The Twin Towers in Lower Manhattan collapsed a short time later. 

Passengers on board a fourth airplane, Flight 93, averted additional destruction by trying to regain control of their plane from the hijackers. 

Due to this intervention, the hijackers downed the aircraft in a field near Shanksville, Pennsylvania. Flight 93’s intended target was likely either the White House or the United States Capitol, according to the George W. Bush Presidential Library.