Metal's earliest titans forged their core sounds in the ‘70s. Sabbath's 1970 landmark “Paranoid” innovated the marriage of crushing power chords and doom-laden nihilism. The year after, Zeppelin's “Black Dog” introduced the art of shrieking vocals and humongous, headbanging grooves. By the decade's end Motörhead hit the scene with a harsh, punk-fuelled blitz that led the genre into the '80s.