On Tuesday, September 11, 2001, the United States was invaded by a series of four coordinated terrorist attacks by the Wahhabi Islamist terrorist group Al-Qaeda. Four airplanes were taken over: two were flown into the Twin Towers of the World Trade Center in New York City, a third hit the Pentagon just outside Washington, D.C., and the fourth crashed in a field in Shanksville, Pennsylvania. Almost 3,000 people were killed, and the attacks triggered major U.S. initiatives to combat terrorism. The attacks changed the world, but despite shared grief in the aftermath, hope, resilience, and unity lifted the nation up.