Ered Wethrin, also known as the Mountains of Shadow, is a mountain range in the fictional world of Middle-earth, created by J.R.R. Tolkien. It lies to the north of Mordor and forms a natural barrier between the lands of Gondor and Mordor. The range is characterized by its rugged terrain and steep peaks, which are often shrouded in mist. The mountains are significant in the lore of Tolkien, as they are home to various creatures and play a role in the history of the Second Age. The Ered Wethrin also includes notable locations such as Durin's Tower and is associated with the struggles between the forces of good and evil throughout the ages.