YouTube's 2012 year in review

This April 19, 2012 file photo shows Canadian singer, Carly Rae Jepsen in London. / Jonathan Short

YouTube released its annual year in review Monday. So who topped the list of top trending videos?

Oppa! You guessed it. Psy came in at No. 1 with the music video for "Gangnam Style." It may be no surprise that the Korean pop star would top the list, considering that "Gangnam Style" won a Guinness World Record for most YouTube video "likes" and took the title of most watched video from Justin Bieber in 2012.

Rounding out the top five spots were: "Somebody That I Used to Know" (Gotye cover) by Walk off the Earth, "Kony 2012," "Call me Maybe" by Carly Rae Jepson - featuring Justin Bieber, Selena, Ashley Tisdale & more and "Barack Obama vs. Mitt Romney. Epic Rap Battles Of History Season 2."

In honor of the year's top trends, YouTube release a mashup of the top videos of 2012. Here's the full list. Watch YouTube's video below.

1. Psy - Gangnam Style

2. Somebody That I Used to Know - Walk off the Earth (Gotye - Cover)

3. KONY 2012

4. "Call Me Maybe" by Carly Rae Jepsen - Feat. Justin Bieber, Selena, Ashley Tisdale & more

5. Barack Obama vs Mitt Romney. Epic Rap Battles Of History Season 2

6. A Dramatic Surprise on a Quiet Square

7. Why You Asking All Them Questions?

8. Dubstep Violin- Lindsey Stirling- Crystallize

9. Facebook Parenting: For the troubled teen.

10. Felix Baumgartner's supersonic freefall from 128k' - Mission Highlights