Edited cuz well I made a mistake.
Also, to add this from wikipedia:
"In-A-Gadda-Da-Vida" is a seventeen-minute rock song by Iron Butterfly, released on their 1968 album In-A-Gadda-Da-Vida, occupying the entire second side of the album. The lyrics are simple, and heard only at the beginning and the end. One of the most memorable parts of the song is the guitar riff, which is also one of the most recognizable guitar riffs in rock music. In almost all of Doug Ingle's other songs, the guitar part was subordinate or equal to the keyboard part, however "In-A-Gadda-Da-Vida" is a rare exception to this, as the song's chorus is centered around the guitar's distorted riff.