Warring factions of undead minions can be found trying to steal or protect the secrets of the ancient city. Do not travel to this place unprepared; it is rumored that only large groups of adventurers stand a chance against the dangers within. - (Source: Dungeons in the Desert)
To enter this instance you must first speak with Muleek Mahaja in the Sinking Sands at ( -357, -144, -1054 ) /waypoint -357, -144, -1054. Afterwards, when you use the pole used to access the Living Tombs you will have the option to enter this instance. Every time you zone out from the instance you must speak with this NPC again.