Every year on the anniversary of the Sept. 11 terrorist attacks, old wounds open as the country remembers a horrific day in U.S. history when a coordinated attack by al-Qaeda killed 2,977 people.

Terrorists flew planes into both towers of the World Trade Center in New York City as well as the Pentagon in Washington, D.C., while another hijacked plane, Flight 93, crashed in Shanksville, Pa., after it is believed the crew and passengers attempted to regain control of the airplane.