We've made it to the quarterfinals of March Metal Madness 2014, the quest to determine the Best Metal Album of the 21st Century. Now, only eight discs remain. So, without further adieu, let's see who's battling it out in the Mosh Pit Region.

In one corner you've got Iron Maiden's 'Brave New World.' The band's 2000 release earned a decisive victory in Round 2 of March Metal Madness, besting Killswitch Engage's 'Alive or Just Breathing.' The disc is a key one in the iconic metal band's career as it marked the return of frontman Bruce Dickinson and guitarist Adrian Smith. It yielded such standouts as 'The Wicker Man,' 'Blood Brothers' and 'Ghost of the Navigator,' among others.

Their opponent will be Slipknot's 2001 classic, 'Iowa.' The unrelenting album edged out Amon Amarth's 'With Oden on Our Side' to advance to the quarterfinals. Corey Taylor and crew earned a pair of Grammy nominations for the album, and also generated such staples as 'The Heretic Anthem,' 'Left Behind,' 'People = S---,' 'My Plague' and 'Disasterpiece' with the 'Iowa' disc.

So now it's up to you. Which is the better 21st century metal album -- Iron Maiden's 'Brave New World' or Slipknot's 'Iowa'? Vote for your favorite and the winner will advance to the March Metal Madness 2014 semifinals.

(This poll will end on Sunday, March 23 at 11:59 PM EST. Fans are able to vote once per hour, so keep coming back to make sure your favorite album wins!)