In the below high definition video we see a new World of Warcraft Cataclysm trailer released at BlizzCon 2009.
The video is about four and a half minutes long and includes a lot of gameplay video as well as lots of ominous voice over work. The expansion brings in a new Alliance race Worgen (werewolves) and a new Horde race Goblins as well as flying mounts. The standard new quests, monsters, dungeons, and level cap increase to 85 is also included. Check it out below.