Turnback Cave

Turnback Cave is a maze-like cave filled with dense fog which is home to the Legendary Pokémon, Giratina. Turnback Cave is located at the north-central region of Sendoff Spring, which itself may only be accessed through the Spring Path. In Diamond and Pearl, in the room Giratina resides in is an inscription that implies the cave is a location where the separation between the real world and the Distortion World is weaker. This is more or less confirmed in Platinum, where a portal to the Distortion World appears in front of the inscription. The only way to locate Giratina is to pass the three pillars before passing through thirty rooms. The best hint to navigate the puzzle is to look at the pattern of rocks on the floor of each room, and enter the door out of the three which has the odd pattern. When the three pillars have been encountered the first time, Giratina will be in the next room. Escape Ropes are not usable, but if one turns back and leaves through the door from which they entered, it will warp them directly to the first room. When the player reaches a pillar and examines it two numbers will appear: the top number indicates which pillar the player is looking at, and the bottom indicates how many rooms have been passed through on the way to it.

After catching Giratina, one can return through the cave to obtain a rare item, depending on how many rooms it takes to reach Giratina's room again. In just 3 rooms, the item will be a Reaper Cloth; 4 to 15 will earn a Rare Bone; 16 to 30 will earn a Stardust. Over 30 rooms, of course, will return the player to the entrance. Riding the Bicycle seems to increase the chance of next entering a pillar room. Rare items regenerate by returning to the cave each time, and they can even be received with Giratina still in the room. In Pokémon Platinum, it will have an item and the portal to the Distortion World.