Smoke on the Water

The song is immediately recognizable by its central theme, a crunching four-tone chromatic progression that is perhaps the single most famous riff in heavy metal music history. This riff, played on electric guitar by Ritchie Blackmore, is immediately joined by drums and contrapuntal electric bass and organ parts before the start of Ian Gillan's expressive vocal. Despite the heaviness of the guitar part, constant movement and interplay within the supporting parts keeps the feel of the song from becoming leaden.
The lyric of the song tells a true story: on December 7, 1971, Deep Purple had set up camp in Montreux, Switzerland to record an album using a mobile recording studio (rented from the Rolling Stones) at the entertainment complex that was part of the Montreux Casino (referred to as "the gambling house" in the song lyric). On the eve of the recording session a concert featuring Frank Zappa and the Mothers of Invention was held in the casino's theater; during the concert a fire broke out (said to be caused by a fan shooting a flare gun) that eventually destroyed the entire casino complex. The "smoke on the water" that became the title of the song referred to the smoke from the fire spreading over Lake Geneva from the burning casino as the members of Deep Purple watched the fire from their hotel across the lake.
Left with an expensive mobile recording unit and no place to record, the band was forced to scout the town for another place to set up. One promising venue was a local theatre called The Pavilion, in an effort to capture a reverberative sound; but soon after the band had loaded in and started working/recording, the nearby neighbors took offense at the noise, and the band was able to lay down backing tracks for only one song before the local police shut them down.