CHICAGO (WLS) -- Monday marks the 55th anniversary of the fire that burned down Chicago's Our Lady of the Angels Catholic School.
On December 1, 1958, 92 students and three nuns died in the fire that to this day, is 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. The building had no sprinklers and only one fire escape.
The tragedy led to sweeping changes in school building fire codes nationwide.