The Magistrates Temple was a beacon of arcane power that many wizards traveled to to study magic. It is located in Dustwallow Marsh in the continent of Kalimdor. It is now overrun with plants and ruled by the Revenant of Burning Souls. Rexxar, Rokhan, Cairne Bloodhoof and Chen Stormstout defeated this ghost lord.
There are two secret areas within the Magistrates Temple. One contains some gold and a tome of each type (intelligence, strength and agility), this area is just to the south of the passage leading to the west part of the temple. In the other area there is a shop hidden (Black Market) selling among other things a Mask of Death. To access this area you need to smash some rock chunks just north of the passage leading to the east part of the temple.