Flames erupted overnight Monday at the Roxy Theatre in Edmonton and sent thick clouds of smoke into the air.
The building was engulfed when firefighters arrived at the west-central location and a second alarm was quickly declared.
The building's walls eventually collapsed. A burned-out shell was all that remained by lunchtime Tuesday.
"It's a tough old fire,'' said deputy fire chief Barry Lamb. "There was a bit of a twinge this morning when I heard it was the Roxy. It is a big part of our city, so it is sad.''
The theatre was built in 1938 as a cinema, but was converted to a live-performance venue in the late 1980s.
Theatre Network, which owns the Roxy, had been celebrating its 40th season as a company.
The Roxy's next show "Cheerleader!'' was to open for a 10-day run on Thursday.
Writer and producer Morgan Smith said the historic theatre was a good place for independent artists.
"It's not just a loss for my company. It's a loss for Edmonton's theatre community,'' she said. "The Roxy performance series gave independent artists a place where they could put up a show on a main stage without having to pay huge rental fees.''
Edmonton Mayor Don Iveson tweeted his dismay.
"Mourning the loss of the landmark,'' the mayor said. `"We're here to help with recovery.''
There was no immediate word on the cause of the fire.
There were no reports of any injuries.
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