Expansion: Cataclysm (2010) is World of Warcraft’s third expansion. It features zones and raids representing all of the four elemental planes (earth, water, air and fire). It also revamped the storylines of all vanilla WoW zones and geographically altered many.
Event: Cataclysm (AKA the Shattering) is the catastrophic event that set the stage for the expansion of the same name. It started off with Deathwing the Destroyer’s emergence from the elemental plane to bestow his wrath upon the world of Azeroth, traveling around the planet and altering many of its landscapes.