Blizzard has posted the first details about a massive new raid, dubbed Ulduar, which will hit World of Warcraft sometime in the spring when Patch 3.1 goes live. Under the "in development" section of the European site for the game, the company has described what it calls the game's "most ambitious raid to date," with a total of 14 bosses and two sections to the raid itself.

Blizzard goes on to explain that the first section will pit a group of players against a massive iron army that guards the gate to Ulduar's inner sanctum. Thankfully, you'll be able to step into the battle on even footing as a small fleet of siege vehicles will be on hand to aid you in the assault. Additionally, for those concerned that end-game content in the Wrath of the Lich King expansion was too easy, the company said that Ulduar utilizes WoW's "Hard Mode" more than any other dungeon.

Blizzard has yet to reveal when Patch 3.1, which includes Ulduar and a host of class changes, is set to be released but promises that it should hit the Public Test Realms "very soon." Further details are available here.