Rock is full of incredible riffs, but if you had to pick the most iconic, most instantly recognizable riff in the history of the genre... I mean, it's gotta be Smoke On The Water, right? That one four-note blues line established Deep Purple as rock legends, and even as pioneers in the developing world of metal, part of the "Unholy Trinity" with fellow hard rock acts Black Sabbath and Led Zeppelin. But how did it all happen?
