World B

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

World B-4
This level is a castle level. It has little lava 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 False Bowser, the Ax, and the Mushroom Retainer.