It's time for Round 2 of March Music Madness! We started with 32 amazing pop songs battling it out for the honorable title of Greatest Pop Song of the Modern Era, and your votes have now narrowed that list down to 16 songs.

Remember, these songs represent the best of the best in pop music from the 1980s, the 1990s, 2000-2009 and 2010-today, so fans will have some very difficult choices to make as they continue to vote in this competition. Will Michael Jackson's 'Billie' Jean' beat Madonna's 'Like a Virgin'? Can Whitney Houston's 'I Will Always Love You' top Backstreet Boys' 'I Want It That Way'? Is 'N Sync's 'Bye Bye Bye' a greater song than Rihanna's 'Umbrella'? Will Carly Rae Jepsen's 'Call Me Maybe' triumph over Katy Perry's 'Firework'? It's up to you to decide on the winner of these music duels (and many more)!

Check out each decade's bracket below to see which songs are still in the running, and click the blue button to start voting for your favorites! You can vote up to once per hour until 12PM ET on March 18. The final winner -- the Greatest Pop Song of the Modern Era -- will be announced on April 8, 2014.

As a reminder, here's a rundown of how it all works:

  1. Each song will battle it out in a duel with another song from its decade in Round 1 of the voting timeline.
  2. Once Round 1 voting wraps, the 16 winning songs will move on to face-off with each other in Round 2.
  3. When Round 2 voting is over, the 8 remaining songs will go on to battle it out in Round 3.
  4. At the conclusion of Round 3, we’ll be down to only 4 songs (one from each decade), which will go head to head for Round 4.
  5. Round 4′s results will leave us with only two finalists — and, after a final round of voting (Round 5), you will have officially chosen the Greatest Pop Song of the Modern Era!