Turnback Cave is a cave found in Pokémon Diamond, Pearl, and Pokémon Platinum. In Diamond and Pearl the maze-like cavern plays a much larger role as it is the home of the Legendary Pokémon Giratina. It is found in Sendoff Spring. A portal to the Distortion World can be found in front of an inscription of the cave in Platinum that in Diamond and Pearl implied that the cave is where the separation between the Distortion World and Sinnoh are weaker.
In order to find Giratina in Diamond and Pearl, the player will have to travel through thirty rooms, the path to the creature not being completely clear. The rocks on the ground can act as an indication on the direction you should travel, though getting to the beast can still be a challenge. Escape Ropes, which are used to escape dungeons, cannot be used in the Turnback Cave, though the name of this place is also the way to get back to safe ground easily: just turn around and enter the door you just came from and it'll send you to the beginning of the cave. Once you find the room with three pillars, that means your close to battling Giratina (note: this is for Diamond and Pearl). After catching Giratina you can return and find a rare item, that item depending on how many rooms it takes until you get to the room with the item. The items include:
In Platinum Turnback Cave has a portal to the Distortion World where you can get the griseous orb.