Plains of Ruin

The Plains of Ruin is the name given to the region surrounding the Swamp Palace in the Dark World of A Link to the Past. It is the dark counterpart of the Great Swamp.

Features
The Plains of Ruin is a very similar area to the one it reflects from the Light World. Its main feature are the marshes surrounding the dungeon to the south, which are heavily populated by Moblins, Zirros, Pikits and other enemies. To the west of the swamp lies a canyon that leads to an impassable dead end, beyond which lies the Swamp of Evil. The Haunted Grove can be found to the northwest, where the Flute Boy can be found in his transformed state. A cave can be found using a Bomb in the northeast side of the marshes where a friendly Thief hides. Chests containing Red Rupees can be found deeper in the cave. The northwest side of the marsh marks the point where someone using the Warp Tile in the Light World will appear. The Swamp Palace itself is easy enough to enter, but progress is impossible without draining the water from the outside into the dungeon. Doing this is only possible in the Light World, where draining the water from the ruins will do the same to its dark counterpart. Travelling north from the Plains of Ruin leads to the Bomb Shop south of the Pyramid of Power, and east leads to the Ice Lake.

Trivia

 * Even though Sahasrahla suggests that changing something in one world will affect its counterpart in the other, the water level in the marshes of the Plains of Ruin and Swamp Palace is one of the few instances where it is actually possible to directly influence one world from the other.
 * Pulling on the bottom of the northeastern-most statue in the swamp will reveal four Blue Rupees. Strangely, performing a Dash Bash on the statue on the small island in the very center will reveal many Apples.