It's MTV's second annual Musical March Madness! MTV News took the 64 biggest names in rock, split them up into four regions, assigned them seeds and puts them up against one another in a single-elimination series of match-ups in a winner-take-all contest. We're leaving it to you to decide an actual champ in this field of 64, so over the next few weeks, fan voting will determine who will emerge as this year's champion. It's all about the fans, and the artist with the most passionate fan base will score the awesome Musical March Madness trophy!

We're at the point in the tournament where every single match-up could lead to a potential champion getting sent home early from competition. The West region has four bands left, and each one could easily hoist the trophy at the end of the tournament. But only two can survive to make the Elite Eight, and only one has the chance to stand tall as the winner of the whole deal.

Voting for all Sweet 16 match-ups will close on Tuesday, March 29 at midnight. As always, you can follow all the voting here.

(1) 30 Seconds to Mars vs. (5) Panic! at the Disco

30 Seconds to Mars are one of two remaining number one seeds in the Musical March Madness tournament, and they have advanced to the Sweet 16 by taking down the likes of Yellowcard and Train. This will be their toughest test yet, as they square off against a very strong Panic! at the Disco team who have stomped on Avril Lavigne and Florence and the Machine. Both bands have tremendously intense fan followings online, but which one will be stronger? The votes will decide their fates!

Check out Dick Bagwell and Vincent Twice previewing the Sweet 16!

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Check out the Musical March Madness bracket and be take a look at the hoops-centric photos of some of the tournament's biggest bands.