UPDATE: Carly Rae Jepsen's 'Call Me Maybe' won in Round 1! Vote for 'Call Me Maybe' 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!

This one's a toughie: It's the sweet sounds of One Direction vs. the ever-catchy Carly Rae Jepsen! On one hand, 1D single-handedly brought back the boy band craze with their tune 'What Makes You Beautiful.' On the other hand, Carly Rae Jepsen exploded onto the pop music scene with her memorable smash hit, 'Call Me Maybe.' Which track should be named the Greatest Pop Song of the Modern Era?

When One Direction came out with their first single, 'What Makes You Beautiful,' they reminded us of every reason why boy bands are the best: The boys are adorable, the song is beyond catchy and we could listen to them sing all day. On 'What Makes You Beautiful' -- which was released in 2011, topped the charts and later won a BRIT Award -- each member of 1D gets a moment for his voice to shine through, while we also get to hear their ear-pleasing harmonies on the chorus. 'What Makes You Beautiful' is pop music at its finest. It's happy, it's bubbly and it sounds amazing.

In 2012, the entire world couldn't stop singing Carly Rae Jepsen's 'Call Me Maybe.' Everyone from Justin Bieber, Selena Gomez and Big Time Rush to the 2012 summer Olympians parodied the hit, which we had stuck in our heads for days on end. 'Call Me Maybe,' which hit No. 1 and was nominated for two Grammy Awards, is upbeat, fun and addictive -- all the makings of a perfect pop song.

Which song is the greater pop hit? You can vote for 'What Makes You Beautiful' or 'Call Me Maybe' once every hour until the polls close on March 11 at 12PM ET. The winning song will move on to the next round of our Greatest Pop Song of the Modern Era competition!