Kanalet Castle
Kanalet Castle is located in the center of Koholint Island in Link's Awakening. It was once King Richard's castle, but rebellious servants kicked him out. Now he is only interested in retrieving the five Golden Leaves still inside the castle.
The King gets Link to acquire these leaves by defeating monsters and solving puzzles, like a miniature dungeon. Once all the leaves are recovered, Link earns the Slime Key from Richard, which can be used to open the third level, Key Cavern.