Blizzard has officially unveiled World of Warcraft's third expansion, "Cataclysm." Discussed at the company's recent BlizzCon event, the expansion will contain a slew of changes, updates, and features. World of Warcraft: Cataclysm will bring two new playable races; a level cap of 85, new zones and quests, and will modify much of the existing world.

As suspected, the two new races will be the Worgen (Alliance) and Goblins (Horde) - and new race and class combinations will be possible. With a raised level cap comes new abilities and talents. New high-level raid content and zones will be introduced, including Uldum, Grim Batol, and the great Sunken City of Vashj'ir. Players can also look forward to guild levels and achievements, PvP objectives and battlegrounds, a new secondary profession, and flying mounts in Azeroth.

Cataclysm will alter much of the base game and current world. Check out a trailer after the jump.