Diamond Steppe Island

Diamond Steppe Island is a diamond-shaped island in The Legend of Zelda: The Wind Waker. Link must use the Hookshot to get to the top of it and enter a maze. The reward there is the Ghost Ship Chart which marks in where will the Ghost Ship be in a certain moon phase. After getting the Ghost Ship Chart at night a glowing ship symbol will appear also on the Sea Chart.

Ironically, this island is also one of the seven recurring destinations of the Ghost Ship.