UPDATE: Katy Perry's 'Firework' won in Round 1! Vote for 'Firework' in Round 2 of the competition here.

Welcome to March Music Madness! Here at PopCrush, we've selected 32 of the most iconic pop songs released from the '80s to today (divided into brackets by decade) -- and now it's your job to vote and decide which song will be named the Greatest Pop Song of the Modern Era. May the best song win!

As part of March Music Madness, Katy Perry and Miley Cyrus are battling it out for the title of Greatest Pop Song of the Modern Era! Katy Perry's 'Firework' quite literally exploded onto the scene, and Miley Cyrus sent tongues wagging (including her own) with her hit 'Wrecking Ball.' Which song is the most iconic?

In 2010, 'Firework' became an anthem for Katy Perry fans everywhere, and the song's universal message (don't be afraid to be yourself) resonated with fans far and wide. Katy's strong vocals on the hit helped to propel the tune to superstardom, and once we heard the electropop-sounding beat, we couldn't help but dance. 'Firework' topped the charts at No. 1 and was nominated for two Grammys.

Miley Cyrus' 2013 single 'Wrecking Ball' is synonymous with her infamous music video, which features the singer swinging naked on a -- you guessed it! -- wrecking ball. While the video certainly helped to garner buzz for the song, it is Miley's natural talent that gives the hit its staying power. Her vocals are powerful and raw, and the lyrics are poignant, relatable and real. 'Wrecking Ball' became Miley's first No. 1 hit in the U.S.

Whose hit is the Greatest Pop Song of the Modern Era? You can vote for Katy Perry or Miley Cyrus once every hour until the polls close on March 11 at 12PM ET. The winning song will continue on to the next round of the competition!