Few bands have made the transformation from cult icons to world-dominating rock stars like Pink Floyd. They began as a vehicle for Syd Barrett, a warped-minded genius whose interest in psychedelia didn’t stop at the music. The band’s 1967 debut album, ‘The Piper at the Gates of Dawn,’ is a milestone of tripped-out elegance and exploration. Barrett’s drug abuse eventually rendered him useless, and by the time Pink Floyd released their 1973 masterpiece ‘The Dark Side of the Moon,’ he was long gone and they had evolved into one of the planet’s biggest bands. Their spacey concept albums – featuring long instrumental passages and heady themes about madness and man’s inability to control his surroundings – reached their peak on 1979’s ‘The Wall,’ a double-record opus focusing on rock-star alienation.