Cerulean Gym

In the anime
Cerulean Gym has appeared in several episodes of the Pokémon anime. On the exterior, the building is a dome-shaped brightly colored Gym with a gigantic painting of a Dewgong on top of it. On the inside, the gym is equipped with a large aquarium and swimming pool.

It first appeared in The Water Flowers of Cerulean City. Ash was heading there so he could earn his Cascade Badge. Misty kept telling him not to go to Cerulean, and he soon discovered why she tried to stop him; her three sisters, Violet, Lily and Daisy, were the gym leaders. However, they had turned the gym into a place for them to put on their water acrobatics shows. They were about to give Ash the badge when Misty intervened. She challenged Ash to a battle, but it was interrupted by Team Rocket. In the end, Daisy gave Ash the Cascade Badge, saying that if it weren't for him, the gym would have been destroyed.

The gym's next appearance was in The Misty Mermaid. While on the way to the Viridian Gym, Misty's Horsea had become sick. Realizing the gym was nearby, Misty decided to go and see if they could make Horsea feel better. The Dragon Pokémon felt better immediately. However, the sisters made Misty participate in one of their water ballet shows. During a Team Rocket battle, the Seel the Sensational Sisters had in their first appearance evolved into Dewgong and saved the gym. Before leaving, Misty left her Horsea and Starmie at the gym, hoping one day to come back for them.

The gym also played key roles in several Pokémon Chronicles episodes. In Cerulean Blues, the gym was in danger of being shut down. Misty, who was recently named gym leader after her sisters won a trip around the world, was successfully able to fix it up and stop it from getting shut down. In the process, she captured a Gyarados. In The Blue Badge of Courage, Sakura challenged Misty to a gym battle and won her own Cascade Badge. Casey visited the gym in A Date with Delcatty, and Misty and Daisy's two Luvdisc, Caserin and Luverin, were stolen by Butch and Cassidy in Luvdisc is a Many Splendored Thing.

Pokémon The Water Flowers of Cerulean City. These are the Pokémon used by Misty in the official battle against Ash Ketchum. In the English version Misty calls the first Staryu's Tackle as Counter, however this move can't be learned by Staryu in the games.

In the Game
In the Game you must travel along a small maze of bridges across the water.