The Clash's London Calling (1979). By the mid-1970s punk had exploded the accepted conventions of rock 'n' roll and driven a wedge between the music's comfortable, MOR centre and its experimental outer strata - just as Stravinsky and Schoenberg had done for classical music at the start of the century. Rejecting pop's traditional blues-oriented themes of forlorn love and individual struggle against an unfeeling world, the Clash produced angry, discordant songs about fascism in the UK and terrorism in the Middle East, and rock 'n' roll could never quite be the same again.