In Pokémon HeartGold, you can gain entry into Cerulean Cave once you've defeated Blue.
It leads to Violet City
Yes, but only in Cliff Cave.
You can find it in the Ruins Of Alph which is south of Violet City.
uh...... if you didn't go into the dark cave in johto and the cave east to cerulean and north of the electric plant. P.S don't mistake the cave in cerulean city. not the cerulean cave!!!!!!!!!!!!!
In the cave behind the final gym there is a whirlpool, go beyond that and there will be another whirlpool, then there will be an exit leading to a grassy area and in there you can find charmander and charmelion (25% chance) then you can evolve it into charizard.
If you are talking about the Dragon's Den in Blackthorn city,then you have to use the moves Surf and Whirlpool to get across. Then you can talk to the Elder.
Use the move whirlpool. If you have a feraligator teach it whirlpool.
It's in the Ice Path.
In HeartGold, I caught mine in the Dark Cave. You can also get them in Cerulean Cave.
You use whirlpool in two main areas. When you have to take the test with the elders in the Dragon's Den, you need Whirlpool. When you want to capture Lugia, you have to use Whirlpool to get into the islands.
There is no Unknown Cave!!
There is no Carmen Cave.
Union Cave.
Mewtwo can be found in the Cerulean Cave in HeartGold.
you need the HM whirlpool (whitch you get it at mahogany town when you shut down the machines lance will give you it)
You can get to the Viridian Forest in HeartGold by going through Diglett's Cave, an entrance to Diglett's Cave is in Vermilion City.