In J. R. R. Tolkien's fictional world of Middle-earth, Mordor is the realm and base of the evil Sauron. It lay to the east of Gondor and the great river Anduin, and to the south of Mirkwood. Mount Doom, a volcano in Mordor, was the goal of the Fellowship of the Ring in the quest to destroy the One Ring. Mordor was surrounded by three mountain ranges, to the north, the west, and the south. These both protected the land from invasion and kept those living in Mordor from escaping.