Cinnabar Island

Cinnabar Island a large island located off the southern coast of the Kanto region, south of Pallet Town.

The island is connected to the mainland by two water routes: Route 20 in the east and Route 21 in the north, leading to Fuchsia City and Pallet Town, respectively.

The journals scattered throughout the abandoned Pokémon Mansion reveal that Mewtwo was created there. The scientists at the Cinnabar Lab (known as the Pokémon Lab prior to Generation VII) have the ability to resurrect Pokémon from their Fossils.

Cinnabar Gym
The Cinnabar Gym is the official Gym of Cinnabar Island, it is based on Fire-type Pokémon and the Gym Leader is Blaine. Trainers who defeat him receive the Volcano Badge. The player is unable to enter the Gym at once; only when they obtain the Secret Key from the Pokémon Mansion can they unlock the door to the Gym. The Cinnabar Gym is a high-tech affair featuring a series of sealed doors. Trivia questions about various Pokémon must be answered to unseal the doors. However, when the player fails to answer a trivia question correctly, a battle with either a Burglar or Super Nerd results, an alternative to unsealing the doors.

Pokémon Mansion
The Pokémon Mansion is a decrepit, burned-down mansion on Cinnabar Island. It got its name because a famous Pokémon Researcher once lived there. The player has to enter the mansion and find the Secret Key to unlock the door of the Gym. Many burglars come to the mansion, trying to steal valuable items that may have been lost in the wreckage, challenging the player to a battle when spotted. Amongst the rubble and wreckage is information that the scientists who once worked there obtained a Mew and impregnated it with the genetically altered Mewtwo, who destroyed the mansion in its escape.

Cinnabar Lab
The Cinnabar Lab, known as the Pokémon Lab is a laboratory located on Cinnabar Island. In the easternmost room, there is a scientist who will revive the Fossils the player has obtained.

Poké Mart
It is right next to the Pokémon Center. Inside, there is a TM vendor. The usual vendor sells battle items as well.