Uldaman

From the introduction: Uldaman is an ancient titan vault buried deep within the earth. It is said the titans sealed away a failed experiment there and then moved on to a new project, related to the genesis of the dwarves. Tales of a fabled treasure containing great knowledge have enticed would-be treasure hunters to dig deeper into the secrets of Uldaman, a task made perilous by the presence of stone defenders, savage troggs, Dark Iron invaders, and other dangers lurking in the lost city. The adventurers have come to Ulduar to uncover its secrets and recover its lost treasures.