At Aakas TP there is an underground area with 11 doors leading to separate instances which are basically an ancient ruined city. A fully repaired key will allow you one entry through a door of the same level as the key. Entry consumes the key. Inside the instance are a whole bunch of mobs only seen in these instances, including a couple of boss mobs. At the end are a number of chests that contain the loot. There is a section of the forum dedicated to the instances. Perhaps worth reading up there and then asking further questions if required.
