Led Zeppelin's defining song – obscene, brutish and utterly awesome. "Way down inside," squeals Robert Plant, "I'm gonna give you every inch of my love" – adding, "I wanna be your backdoor man!" just for extra romance. His post-verbal singing is even dirtier, especially around the 4:30 mark, where he starts saying "love," and then shoots his wad into a black hole of echo. (The ghost vocals were a happy accident, the result of a bleed-through from an unused vocal track that Jimmy Page decided to leave in.) Years later, Plant freely admitted his heavy lyrical debt to "You Need Love," by uncredited blues-master Willie Dixon (who sued and won); "I just thought, 'Well, what am I going to sing?' That was it, a nick. Now happily paid for." But "Whole Lotta Love," recorded at London's Olympic Studios and mixed in New York, was far more than a remake. The midsection is a black-light head trip, a tornado of orgasmic moans, cymbal teases and shivering theremin foreplay, all magnified by wild stereo-panning. Page's pumping riff – made with a metal slide and augmented with some backward echo – is one of the most straightforwardly bruising to ever come out of a Les Paul, and John Paul Jones and John Bonham back it up thrust for thrust. Said Page, "Usually my riffs are pretty damn original. What can I say?"