World B (Super Mario Bros.: The Lost Levels)

World B is the third secret world that was first featured in the game Super Mario Bros.: The Lost Levels, following World A (Super Mario Bros.: The Lost Levels). If the player completes this world, the player will gain access to go to World C.

World B-1
This is an overworld level with a few bottomless pits, a green springboard and a Coin Heaven.

World B-2
This level is an underwater level which has several features including a long Fire Bar near the end.

World B-3
This level has very long pits which require the use of several platforms to be cleared.

World B-4
This level is a castle level which has a few lava pools in it. The second, third, and fourth pipes all go back to the first pipe (all the pipes contain red Piranha Plants). The last pipe leads to a Warp Zone to World D. At the end will be the Bowser Impostor, the axe, and the Toad.