Warp Zone (Super Mario Bros. 3)

Warp Zone, also known as World 9, is a secret world in  Super Mario Bros. 3 . This world is a secret place in the Mushroom World, and is not accessed by clearing World 8. No actual levels exist in this world, and it only serves to skip to another world. The game cannot be saved in Warp Zone.

Directions
In order to get to the Warp Zone, the player must use the Warp Whistle. Where the player ends up is dependent on the world he used the Warp Whistle in. If the Warp Whistle is used in World 1, he can choose from Worlds 2-4. If the Warp Whistle is used in Worlds 2-4, he can choose from Worlds 5-7. If the Warp Whistle is used in Worlds 5-7, the player will be brought to World 8. Using a Warp Whistle while they're already in the Warp Zone leads them to the section leading to World 8.

Geography
The Warp Zone consists of a small island, littered with Warp Pipes leading to other Worlds. Any other geography cannot be defined, due to there being no actual levels. No inhabitants or rulers live on this island.