Minus World

The Minus World is a glitch found in Super Mario Bros. It is an underwater level that has no end, meaning that once there, Mario or Luigi is doomed to die by either running out of time or being killed by enemies. The level got its name because, when in the Minus World, the top screen says that you are in World 0-1, effectively World -1.

To get to the Minus World, Mario must go to World 1-2 and stand on the pipe that leads to the flagpole at the end of the level. Mario should break two blocks, leaving the one to the far right. Now, Mario should move to the far left end of the pipe, facing left, and jump into the air. Press right while in midair. When Mario comes back down, he should be in a warp room if everything was done correctly. Once the worlds in the room appear, take the pipe to the far left, and Mario will himself in the Minus World.