The small town of Montreux, Switzerland, became a place forever linked to rock history on Dec. 4, 1971. A fire at the Montreux Casino during a concert by Frank Zappa and the Mothers of Invention inspired Deep Purple's classic "Smoke on the Water."

The Mothers were performing "King Kong" – about 80 minutes into the show – when, during Don Preston's synthesizer solo, someone shot off a flare gun. The flare hit the wooden roof and quickly spread.

Originally, the band treated it with their customary irreverence. "Fire!" shouted background vocalist Howard Kaylan. "Arthur Brown in person." But they soon realized the danger and Zappa had the composure to tell everybody to head calmly toward the exits. As depicted in the lyrics to "Smoke on the Water," Claude Nobs, the director of the Montreux Jazz Festival, ran in and out of the building to help fans escape.

"They were very organized," Zappa said in an interview shortly after the fire. "I was just lucky that many of [the fans] were able to speak English, because I didn't know what to say to them in French." You can listen to the interview above, even though it's difficult to understand at times due to an off-screen translator.

Attendee Peter Schneider wrote a blog post in 2009 about what it was like inside the casino. "The fire spread so quickly that all the people in the front were trapped," he later recounted. "There was a large door on the right hand side as you face the stage but I do not know if it was open or closed.

"I stood behind the crowd who were trying to get out through the large glass windows which covered the whole of the front of the building from one side to the other. I owe my life to a Swiss fireman who came in with a huge axe and started to break the windows one by one, starting from the left towards the stage," Schneider added. "The glass smashed to the ground, and all the people in the front started to jump out. The building was on the second floor, or at least half a floor up, so it was quite a jump."

Shortly after everyone got to safety, the fire reached the building's heating system, causing an explosion. Fortunately – miraculously, even – no one was killed in the blaze. According to Zappa, most injuries were minor cuts and burns, with only a few people going to the hospital. But the casino was completely engulfed in flames, and all of the band's equipment was destroyed, except, oddly enough, a cowbell.

The band was forced to use rented gear for its next gig at the Rainbow Theater in London six days later. However, that also ended disastrously when, during the encore, Zappa was pushed offstage by a fan into the concrete orchestra pit. The injuries forced Zappa to spend nearly a year in a wheelchair.

However, Schneider disputes one particular aspect of the famous story. "The fire was started by a young man from Eastern Europe (who fled the very next day back home)," he continued. "I do not think that it was started by a flare gun as it says in the song, but by the boy throwing lighted matches in the air, and one of them got stuck on the very low ceiling. ... So the fire started right above where the boy was sitting on the low-lying ceiling beams."

In an odd coincidence, Zappa died on Dec. 4, 1993, the 22nd anniversary of the fire.

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