The rise of Bernie Sanders has no doubt been one of the more fascinating political stories of 2015 – a year that was not short on fascinating political stories. When he announced his run in the spring, few thought the self-described democratic socialist would be such a strong opponent against Hillary Clinton, but his impact in the race has been significant: He's raised significant money, without relying on super PACs, and has pushed Clinton to the left in very real ways.

Whether you're full-on feeling the Bern, or are just a political observer, it's worth taking a look back at the year Bernie Sanders transformed from "that socialist from Vermont" to a national political phenomenon.