Swamp of Evil

The Swamp of Evil is the Dark World equivalent to the Desert of Mystery.

Location
The swamp is located southwest of the Dark World. However, it's inaccessible from the overworld map of the Dark World, and can be entered only by using the flute in the Light World to summon the bird from Kakariko Village's weather vane. Once in the proper spot, Link lifts a rock to unveil a portal that takes him to the Dark World's swamp area.

Features
The Swamp of Evil is a dark and filthy place enduring a torrential downpour, and home to various swamp-dwelling creatures; here Link can find a cave with a Piece of Heart, and it's also home to the mysterious Ghost of Misery Mire. As previously mentioned, the Light World equivalent of this rainy field is the Desert of Mystery, minus the original entry paths which do not exist in the Dark World. Near where the exit to the overworld should be, Link can find a spot and use the Magic Mirror to warp to the Light World and find himself over a hill, where the Bombos Medallion can be gained.

The entrance to the Misery Mire can be found here. It can only be accessed by using the Ether Medallion on a platform with the medallion's sign on it.