On September 11, 2001, filmmakers Jules and Gedeon Naudet were filming a documentary on a rookie New York City firefighter when they noticed a plane overhead. That plane would hit the World Trade Center. The firefighter and the Naudets rushed immediately to the scene. The Naudets filmed throughout Sept. 11 and the days afterward from the firemen's perspective, as it became clear to them that this was the only known footage from inside the Twin Towers that day. Written by Brian Henke