The Desert of Mystery is a location from The Legend of Zelda: A Link to the Past. The Desert of Mystery can be found in southwestern Hyrule, and is the location of the Desert Palace, the second dungeon in the game. The Book of Mudora is required to enter the Desert Palace.
According to the official Legend of Zelda series website, the Desert of Mystery was originally known as the Haunted Wasteland in the story of The Legend of Zelda: Ocarina of Time. However, the accuracy of this website is often disputed by fans.
Points of interest
In the area is a cave, whose entrance is sealed by a Breakable Wall, which can be destroyed with a Bomb. Inside the cave, there is a hermit named Aginah, who recognizes Link as the hero who will save Hyrule and wishes him luck in his travels. There is also another Breakable Wall that hides a Treasure Chest containing a Piece of Heart.
The Desert Palace is located in the northwestern region of the Desert of Mystery. Upon reaching its main entrance, Link finds that it has been blocked by a statue. By translating the text written in the ancient Hylian Language on the nearby stone pedestal, Link can cause this statue and two others to rearrange themselves in a way that allows the hero to enter the palace.
Once the first half of the Desert Palace has been completed, Link must exit the dungeon and use the Power Glove in order to move the stones that block the entrance to the other half of the dungeon, where the Lanmolas that serve as the dungeon's bosses can be found.
The Bombos Medallion can be found in the Desert of Mystery. If Link uses the Magic Mirror near the dead end that should have been the entrance to the Desert of Mystery in the Dark World, he appears in the Light World on top of the ledge where a strange stone with inscribed Hylian letters on it sits. When Link uses the Book of Mudora to decipher the letters, the Bombos Medallion descends from the sky.