Ragnarok: Crash Course World Mythology #24

Ragnarok! It's the end of the world, Norse style. It's got everything you want in an apocalypse. Earthquakes, destruction, armies of the dead, a giant evil wolf, giants with flaming swords, and a kind of happy ending. It's got it all. But is it really Norse? It wasn't written down until after Christianity had arrived in Europe. So how much influence is there?