Cinnabar Island is an island in Kanto. The Pokemon Mansion is here. Blaine is the Gym Leader here in Generation I and Generation III. The Pokemon Lab is here. In Gen. II, a volcano erupted leaving only the Pokemon Center and forcing Blaine to move to the Seafoam Islands. The coast on the East side is famous for the Missingno. glitch. Even without talking to the old man, you will still encounter pokemon that shouldn't be there, but so far the only ones that i know you encounter are PIDGEY and RATTATA.