On September 11, 2001 at 9:37AM American Flight 77 slammed into the Pentagon killing 184 people. What happened behind the walls of the Pentagon is a largely untold chapter in history. Fifteen years later, survivors and first responders shed light on that tragic day.

Reports of a second incoming plane circulate amongst those watching the skies and those on the ground. In response, rescuers race to evacuate the injured and try to find safety.

The Pentagon’s blast-proof windows were installed to keep those who work inside the building safe. They succeeded in saving the lives of many during the initial impact, but now, to the horror of the rescuers and survivors, the very same windows are preventing survivors from escaping.

Flight 77 hits the Pentagon, ending the lives of 184 people. Survivors inside the Pentagon fight for their lives as they search for safety in a labyrinth of smoke and fire. Those still stuck inside and those who have made it out to safety, struggle to save their injured co-workers.

The layout of the biggest office building in the world, the Pentagon, is described. A graphic illustrating the five wedges and five rings is seen. Some people inside the Pentagon know an attack is underway, but most are unaware that they are the next target.

Marking the 15th anniversary of the September 11, 2001, terrorist attacks on the U.S., this program tells the rarely told stories of the attack that took place at the headquarters of the U.S. Department of Defense, in which 184 people died. Premieres Tuesday, September 6 at 8/7c. #911PentagonPBS