John Fanning lost his wife during the blaze at the Blue Bird Cafe on Sept. 1, 1972.
"She was sitting at my table, I ordered a beer and then all of a sudden flames came up through the floor and she went through the floor," he said.
"That's all I remember."
It was a painful return to Montreal on Friday for Linda Nagy, a survivor whose hands and face were burned by the fire. She had not been back to the city since the tragedy.
Nagy, from Sarnia. Ont., said she was a 16-year-old who was visiting aunts and uncles when a family friend offered to take her to the Blue Bird that night.
"I remember seeing fire coming up the staircase because I was sitting just across from there and then going into the back room trying to escape," she said in an interview.
''I found myself in front of a door and it was locked and I asked for God's help to help me out and that door opened — I don't know who did that, that day, but I'm here."
That fateful night, the Wagon Wheel, a club located just above the Blue Bird, was filled with about 200 people.
Three drunk men, upset at being denied entry by a bouncer, set fire to a staircase that served as the main entry to the Wagon Wheel. Many victims unable to escape died of smoke inhalation.
Commemorative services began Friday as hundreds packed a memorial mass at the Mary Queen of the World Cathedral.
The solemn service included a wreath-laying ceremony that also remembered firefighters who have died in the line of duty over the years.
A classic red fire truck then led a procession which walked several blocks to Phillips Square where the memorial stone, near the scene of the tragedy, was unveiled.
Along the way, the marchers, who included city firefighters, passed in front of the parking lot where the Blue Bird Cafe was once located.
As an honour guard removed the black cloth which covered the plaque containing the names of the 37 victims, survivors, family members and friends hugged each other and several wept.
One by one, they then each laid a white rose over the names of those close to them who had died in the inferno.
Most of the 37 victims were in their teens and early 20s. Another 56 people were injured.
Further commemorations will take place on Saturday.
Three men were convicted. James O'Brien and Jean-Marc Boutin were found guilty of second-degree murder, while Gilles Eccles was convicted of manslaughter.
The fire was the worst in Montreal since the Laurier Palace theatre fire in 1927 in which 78 children died while watching a silent comedy film.