Duncanthrax built the Glass Maze on a whim, located underground near Egreth Castle, just off the western branch of the Great Underground Highway, in order to amuse his friends, and torture his enemies.

It is a labyrinth of 27 cubicles, full of pitfalls. The entrance to the Glass Maze was a magnificent Hall, graced with a wonderful statue of King Duncanthrax himself. The base of this statue was engraved with the words: "I, Duncanthrax, King of Quendor and all its subjugated outlands, invite you to sample the delights of my Glass Labyrinth."

Since the abandonment of Egreth, the maze lies unused said that there are secret controls that change the position of the walls, ceilings, and floors, or that a sufficient magical force could to the same thing, but only once, in the struggle to thwart the demon Jeearr, has such a thing been recorded.