After you beat the gym and visit Bill, There is a house behind the gym that you enter to get to the other side. After you get to the other side you'll have to battle team rocket. When you beet him, he will give you the TM dig. go down, but don't jump over the rocks that are there. and Poof! your out of Cerulean City.
Chat with our AI personalities
yes. you may find them at: Cerulean City Five Island Water Path Cerulean Cave
The 8 Gyms in Leaf Green are in Pewter City, Cerulean City, Vermilion City, Celadon City, Saffron City, Fuchsia City, on Cinnibar Island and in Viridian City.
Basically it's the 3 (and pikachu) beginning Pokemon you got to choose in red and blue version, you can get them from people in the game one is in cerulean city, the other on route 24 and the last in vermilion city.
Once Pikachu is happy with you, talk to the lady next to the gym in Cerulean City. She will give you a Bulbasaur.
Bottom of Cerulean City