Cerulean Cave

Cerulean Cave, introduced as Unknown Dungeon, is a cave located in the northwest corner of Cerulean City in Kanto. While it is technically a part of Cerulean City, it can only be accessed via the waterway on Route 24.

Cerulean Cave is home to a wide variety of high-level wild Pokémon. The Pokémon League only permits Trainers who have entered the Hall of Fame to enter, then players must further prove themselves before entering the cave, which is done by completing the quest on Sevii Islands and restoring the Network Machine of the Pokémon Network Center to operational status.

Cerulean Cave is a large underground complex of maze-like tunnels which extend out from Cerulean City to the mountains beyond. The entrance to the cave looks like it has been carved out from a hillside, forming an indented entrance into the hill.