Fleetwood Mac are one of the most popular, constantly evolving bands in rock history. Iron Butterfly were one of first acts to prove that complex hard rock could break through to a large audience. Sadly, only one of these two groups can move onto the second round of this month's UCR Hall of Fame election.

Each month, our readers will determine which of eight legendary artists or bands is immortalized forever for their contributions to classic rock history. Iron Butterfly is largely remembered for their immortal 17-minute epic 'In-A-Gadda-Da-Vida,' but as you can see from our Top 10 Iron Butterfly Songs list, they created many more great tracks during their brief time together.

Originally conceived as a hard-hitting blues-rock band showcasing the skills of Peter Green, Fleetwood Mac found their greatest fame years later when Lindsey Buckingham and Stevie Nicks joined and turned the group into a highly polished pop-rock outfit known almost as much for their interpersonal dramas as for their gorgeous songwriting. Their 1977 album 'Rumours' is one of the biggest-selling records in history.

So which one of these two admittedly oddly named bands will move onto the semifinals of this month's election? It's your call! You can vote once a day from now until 11:59PM ET on June 16. You can read the Hall of Fame’s official rules right here. Be sure to mark your calendars for July 1, when the third entrant into the Ultimate Classic Rock Hall of Fame is revealed.


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Ultimate Classic Rock Hall of Fame
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