Desert of Mystery

The Desert of Mystery is located in the southwest corner of Hyrule in A Link to the Past.

Features
The desert is the location of the second dungeon in the game, the Desert Palace, which contains the Pendant of Wisdom.

The Desert of Mystery is a wide open area filled with cacti. The only other features are the Desert Palace, a few cliffs, and caves. The area is swarming with Vultures and Geldmans, as well as bombs that explode at close range, making it somewhat of a nuisance to traverse.

On a cliff in the Desert of Mystery, only reachable with the Flute, there is a portal to the Dark World hidden by a rock. This is the only way to enter the Dark World equivalent of the Desert of Mystery, Swamp of Evil.

A Link to the Past comic
The Desert of Mystery is also featured in the A Link to the Past comic. Before Link can head out to the desert, however, Sahasrahla's Wife warns Link  that traveling through the desert will not be easy since the "fierce   winds and shifting sand" have bested even the most capable adventurers. Just then, the young boy who Sahasrahla left in charge of his wife gives Link a hang glider so that that he can use to traverse the Desert of Mystery with ease.

Using the "miracle wings", Link flies over the Desert of Mystery and locates the ruins of the Desert Palace. Using the Book of Mudora to translate the runes he finds, the ruins begin to sink to reveal a scorpion statue that has the Pendant of Power hanging on it. Before Link can approach it, he sinks into the quicksand and resurfaces on top of a Lanmola. Link tries to attack it with his sword but to no avail; however, he manages to retrieve the Pendant of Power from the statue and uses it to defeat the Lanmola.

Trivia

 * While many other games have desert areas, A Link to the Past is the only one the Desert of Mystery appears in. In other games, the deserts are often replaced with the Gerudo Desert.
 * The only moment in the game where the Book of Mudora is required to complete the game is in the Desert of Mystery, when entering the Desert Palace.
 * The Desert of Mystery is the only location in A Link to the Past where the Book of Mudora is used twice. Once to enter the Desert Palace, and a second time to get the Bombos Medallion atop a cliff after Link's gone to the Dark World.