From Bulbapedia, the community-driven Pokémon encyclopedia.
Cerulean Cave (Japanese: ハナダのどうくつ Hanada Cave), sometimes referred to as the Unknown Dungeon (Japanese: ななしのどうくつ Nameless Cave) in Generation I, is a cave located in the northwest corner of Cerulean City in Kanto. The cave is home to a wide variety of high-level wild Pokémon. Only Trainers who compete and win in the Pokémon League at Indigo Plateau may enter, due to the potency of the Pokémon in the cave. At the end of the cave lies Mewtwo, the only one of its species in the game.
Cerulean Cave has had many different layouts over time, getting a change from not only one Generation to the next, but also from one game release to the next. In FireRed and LeafGreen, the layout is true to that of the original Red and Green games, aside from the addition of Rock Smash boulders.
Another addition in FireRed and LeafGreen lies in the fact that Trainers are now required to further prove themselves before entering the cave, which is done by completing the quest on Sevii Islands and restoring the Network Machine to operational status. Another change is in the fact that more Pokémon can be found only by fishing, while wild Pokémon found just by walking around in the cave are reduced in number. In Generation I, there are also several species that make no sense to be in the cave, such as Dodrio and Pokémon that are otherwise only obtainable by stone-induced evolution; however, this has been fixed in Generation III, at the cost of some of the wild Pokémon diversity.
In Generation II, Cerulean Cave completely collapsed. However, the leftovers of Mewtwo's presence can still be found in the lake near the cave, in the form of the item Berserk Gene.
In Pokémon HeartGold and SoulSilver, Cerulean Cave has been rebuilt and Mewtwo can once again be found inside, although, as in previous generations, a person stands in the way until the player has proven him or herself by defeating all eight Kanto Gym Leaders.
Misty entrance to Cerulean Cave
Cerulean Cave is a large underground complex of maze-like tunnels which extend out from Cerulean City to the mountains beyond. With the misty, dark entrance positioned on the outskirts of Cerulean City, only to be accessed from Route 24 or a section of Route 3, the cave has been renowned for its mystery. The entrance to the cave looks like it has been carved out from a hillside, forming an indented mouth into the hill. A thick layer of mist surrounds the area and silhouettes of dark trees can be seen in the background. An Ace Trainer guards the mouth of the cave and only allows powerful Trainers who own all eight gym badges and have competed in and won the Pokémon League beating the Elite Four to enter its premises.
It is unknown whether Cerulean Cave was formed naturally through the process of weathering, built by man through the use of excavation, or perhaps by the Pokémon Mewtwo, which is the cave's most powerful resident; however, it is most likely formed by natural means. Pictures of the cave suggest it is a solutional cave, which was formed in the soluble rock, limestone, which is dissolved by natural acid in groundwater that seeps through the rock, forming the cave systems. Because of this, stalactites and stalagmites have formed in the cave while water rises from the floor and drips from the ceiling.
Because of its damp and dark environment, Cerulean Cave hosts a large array of different Pokémon well and truly beyond average levels. These Pokémon have possibly gained this amount of experience from living in an area uninhabited by humans, adapting to their environment. Pokémon such as Golbat and Venomoth are able to see their way through the darkness, while other powerful Pokémon like Hypno and Rhydon live in their habitat. All the Pokémon inhabiting Cerulean Cave have levels well over 40 and 50, with some even rising as high as 60, matching the levels of the Elite Four and even the Champion, which is why the cave was sealed off and is forbidden to be entered unless Trainers own all eight gym badges and have competed in and won the Pokémon League, beating the Elite Four. At the deepest point of the cave lives Mewtwo, a Pokémon that can only be found in Cerulean Cave alone. Mewtwo was created by man in the Pokémon Mansion before it became too powerful and escaped, destroying the Mansion and exiling itself to the cave, never to be seen again. If Mewtwo had created Cerulean Cave as a residence during this event, the cave would have been recently formed – according to the Pokémon Mansion journals, Mewtwo had escaped the Pokémon Mansion only recently.
Cerulean Cave has had many different layouts over time, getting a change from not only one Generation to the next, but also from one game release to the next. In FireRed and LeafGreen, the layout is true to that of the original Red and Green games, aside from the addition of Rock Smash boulders. However, besides these changes, the first floor has a large underground lake which covers most of the area. Using the complex of stairs and ladders, Trainers can make their way around the lake and the first floor of the cave. They will reach the first floor, which has no underground river, but a like maze-like structure formed by large boulders and rocks that must be maneuvered around in order to reach the end. Once Trainers get through the maze formation, they are able to climb the ladders and get around the underground lake on the basement floor, which will lead them straight to a dead end and to Mewtwo.
The layout of the cave has been tweaked several times in the past, particularly in Generation I; however, the layout depicted in FireRed and LeafGreen looks almost exactly like the design in the Japanese versions of Red and Green, but with improved graphics.
- In Generation I, any Pokémon that can only be found in the Unknown Dungeon is listed as "area unknown" in the Pokédex. This was fixed in Generation III, however. Whether this was intended or just a glitch is unknown.
- Though its design varies with each iteration, the version of it found in Pokémon FireRed and LeafGreen is very heavily similar to the one in the original Pokémon Red and Green, which was never released outside of Japan. The only difference is the Generation III addition of Rock Smash boulders.
In other languages
- Spanish: Mazmorra Rara (Generation I) and Cueva Celeste (Generation II, III, IV)
- Italian: Grotta Ignota (Generation I) and Grotta Celeste (Generation II, III, IV)
- German: Geheimdungeon (Generation I) and Azuria-Höhle (Generation II, III, IV)
- French: Grotte Inconnue (Generation I) and Grotte Azurée (Generation II, III, IV)