Great moments in obscure rock 'n' roll: Cactus, "Rock 'n' Roll Children," 1971

Here's another from the American and less polished version of Led Zeppelin, best-known for their covers of other songs, but with an occasional memorable original, like this one from their second album: 

 And here's a great cover of an old Howlin' Wolf number, from their third album (also 1971):