27 FBI photos you must see of the Pentagon on 9/11

Five al-Qaeda militants hijacked American Airlines flight 77 on Sept. 11, 2001. The plane was on its way from Dulles Airport outside of Washington, D.C., to Los Angeles. The plane made it as far as eastern Kentucky before the terrorists took over the plane and slammed it into the Pentagon.

The FBI added 27 images the agency took on the ground that day to their photo vault, as first responders raced to rescue the wounded and remove the dead from the shell of the nation's symbol of military power.

Debris from the plane and the building are highlighted in the Mar. 23 release of photos. The attack killed 125 people in the Pentagon, as well as all aboard the flight.

The Boeing 757 took off from Dulles ten minutes early. Some of the passengers were teachers and students on a National Geographic Society field trip. Authorities estimate the flight was taken over between 8:51 and 8:54 in the morning, as the last communication with the real pilots was at 8:51. The terrorists were led by a trained pilot, as the other four herded the passengers to the back of the plane to prevent them from re-taking the aircraft.

The hijacker pilot did not respond to any radio calls. With no transponder signal, the flight could only be found when it passed the path of ground-based radar. At 9:33 am, the tower at Reagan Airport contacted the Pentagon, saying "an aircraft is coming at you and not talking with us." At 9:37:46 am, American Airlines Flight 77 crashed into the Pentagon. Listen actual radio traffic about the flight at NPR. USA Today detailed the victims of Flight 77.