The Rolling Stones released "Gimme Shelter" just days after Meredith Hunter's murder at the Altamont festival in 1969 -- fitting, because the song has become nearly synonymous with the violence and turbulence of the late 1960s. Keith Richards reportedly wrote "Gimme Shelter" in just 20 minutes, then crafted the ominous introduction using an acoustic-electric guitar modeled on one of Chuck Berry's favorites. The finishing touch came from American soul singer Merry Clayton, who added an eerie wail to lines like "Rape, murder, it's just a shot away." "It was a very rough, very violent era," Mick Jagger told Rolling Stone in 1995. "That's a kind of end-of-the-world song, really. It's apocalypse; the whole record's like that."