The progressive-rock supergroup Emerson, Lake and Palmer were never really notable for their restraint, either in the complexity and execution of their music or in their over-the-top live shows. Keyboardist Keith Emerson was a particularly flamboyant live performer, but his onstage antics could have cost him his career on Feb. 2, 1973, when he injured his hands in an accident involving pyrotechnics.
The roots of progressive rock, or 'prog' if you prefer, was the seemingly natural outgrowth of psychedelia. Its roots can be traced back to the Beatles' wildly experimental studio adventures during 1966 and 1967. Bands took the ball from the Fabs and ran with it into previously unimaginable territory.