When George Harrison met John Bonham, the Beatle told the Led Zeppelin drummer, "The problem with your band is you don't do any ballads." Singer Robert Plant and guitarist Jimmy Page could have taken umbrage — they had already written the gorgeous "Going to California" two years earlier, for God's sake. Instead, they rose to the challenge. "The Rain Song" is seven minutes of exquisite heartache, complete with Mellotron strings from John Paul Jones. And in tribute to Harrison, the opening two notes are recognizably borrowed from his ballad "Something."

Led Zeppelin took the title of Houses of the Holy from their term for the oversize arenas and stadia where they played live. After five years together, they were ambitious and confident enough to believe they could meet any musical challenge; this album even includes a swinging take on reggae, "D'yer Mak'er." "Over the Hills and Far Away" builds in intensity just as relentlessly as "Stairway to Heaven." And "The Ocean," the love song for Plant's baby daughter that closes the album, is a mighty stomp that could rattle the teeth of fans in the last row of Madison Square Garden. The epic scale suited Zeppelin: They had the largest crowds, the loudest rock songs, the most groupies, the fullest manes of hair. Eventually excess would turn into bombast, but on Houses, it still provided inspiration.

“Time to Pretend”

Listening to MGMT’s breakthrough song, one might interpret it as being about the excesses of rock stardom, but it’s actually about the duo’s pet praying mantis. Ben Goldwasser and Andrew VanWyngarden told Rolling Stone they got the idea from the insect's jerky movements. The mantis died, but the two bandmates kept the egg sack and allowed the hundreds of eggs to hatch. “We tried to name them all, but they died after a day,” said Goldwasser, with VanWyngarden chiming in, “But the praying mantis dance inspired us.”