In Norse mythology, Ragnarök is a series of future events, including a great battle, foretold to ultimately result in the death of a number of major figures (including the Gods Odin, Thor, Týr, Freyr, Heimdallr, and Loki), the occurrence of various natural disasters, and the subsequent submersion of the world in water.
https://en.wikipedia.org/wiki/Ragnar%C3%B6k