Are you thinking of a different location? Maybe you're thinking of:
* The Cave of Origin: Located in the far north of the Sinnoh region, it's a special cave with a unique storyline.
* Stark Mountain: A large mountain with a network of caves, including the entrance to the Spear Pillar, where you fight the legendary Pokémon Dialga and Palkia.
* Iron Island: This location has a series of caves and is home to the powerful Pokémon Magnezone.
Please clarify what location you're looking for, and I can give you more specific information about how to access it.