We're at the height of the summer touring season, and arenas and amphitheaters are full of shows featuring great opening acts. Cheap Trick is opening up for Aerosmith, Alice Cooper is opening for Iron Maiden and later this year Patti Smith will open for Neil Young & Crazy Horse.
Our question for you: What is the greatest double bill in rock history? You can go back 45 years and vote for the Who opening for Herman's Hermits, step into 1978 with Van Halen on the undercard for Black Sabbath or five years after that with Motley Crue opening for Ozzy Osbourne. Feel free to step away from rock and vote for Britney Spears supporting N'Sync in 1999, or even this year's Justin Bieber/Carly Rae Jepsen tour. Just please only vote for one tour.