If we were to list the most influential events of the first decade of the 21st century for both the United States and the world, there's no doubt 9/11 would top the list. On September 11, 2001, several terrorists chose the ironically significant day of the American emergency contact number to hijack four commercial airliners and launch suicide attacks on multiple locations. Apart from United Airlines Flight 93, which crashed in Shanksville, Pennsylvania, due to passenger resistance, the other three hit their intended targets with precision: the Twin Towers of the World Trade Center in New York and the Pentagon in Washington D.C.