On December 4, 1971, Deep Purple was in Montreux, Switzerland, to record their new album at the Montreux Casino. That night, they attended a concert by Frank Zappa and the Mothers of Invention, which was the last one before the venue closed. Toward the end of the show, an enthusiastic fan fired a flare toward the ceiling, which was covered in rattan. The material caught fire quickly, and the blaze spread devastatingly, completely destroying the casino. Fortunately, there were no fatalities, but there was widespread chaos. Claude Nobs, director of the Montreux Jazz Festival, actively helped rescue several people trapped in the basement. Frank Zappa even broke a window with his guitar to facilitate the evacuation. The members of Deep Purple watched the fire from their hotel and saw the smoke rising over Lake Geneva. That image directly inspired the song “Smoke on the Water,” which recounts almost verbatim what happened that night.