On December 1, 1958, 95 people, including 92 students and three nuns, died in that fire.
To this day, it's still among the worst school fires in United States history.
Investigators believe the fire started in a basement stairwell.
The brick structure was made of wood on the inside.
It had no sprinklers and only one fire escape.
The tragedy led to sweeping changes in school building fire codes nationwide.
