That debut by Blue Cheer was the first album I heard that had a "heavy" sound, Zeppelin's the second. The former contained the worst "music" I had yet heard at the time of its release (1968), but then in 1970 Black Sabbath's debut appeared.
Everyone considers Spinal Tap funny, right? But not Blue Cheer and Black Sabbath?!.Unintentionally, but still.....