Minus World

The is a glitch level found in Super Mario Bros., and is arguably regarded as the most famous glitch in video game history. It is an underwater level (exactly like World 2-2 in geography and enemy locations) that cannot be finished (the pipe at the end is glitched and takes the player back to the start), meaning that once there, Mario or Luigi is doomed to lose all of their lives by either running out of time or being defeated by enemies. The level got its name from fans because, when in the Minus World, the top screen says that Mario is in World -1. This is because of a glitch in the panels displaying the numbers. Because the Minus World is actually World 36, the game displays a space (its graphic for the never-used number "36") for the World number, leading to -1.

How to perform the glitch
Mario can get to the Minus World by going to World 1-2 and standing on the pipe that leads to the Flagpole at the end of the level. Mario should move to the far left end of the pipe, then duck while facing left. While ducking, the player should jump. While in the air, Mario should move right, so that when he's about to come back down, he should be just under the ceiling next withing this moment. It may take the player several tries, for Mario must land in an exact spot on the pipe in order to travel through it. If done correctly, he will automatically move through the pipe (without the screen moving) and then through the wall and he will appear in the warp room.

There is another, minor way on doing this. Mario should break two blocks on the ceiling, leaving the one on the far right. He should move to the far left end of the pipe and jump to the right. He doesn't have to duck as he can try to hit just on the bottom-left of the block (without actually destroying the block). This should glitch you though to get thought the pipe and wall, but doing it this way is harder as it may take some trys and a lot of time.

If everything was done properly to get to the warp zone, Mario will see the three pipes in front of him from the Warp Zone. If Mario enters the pipe to the far left or far right, he will find himself in the Minus World. If he goes in the pipe in the middle, it will bring him to World 5-1. If the player makes the brick wall on the far right visible, however, the glitch will end.

Famicom Disk System version
In the Famicom Disk System version of Super Mario Bros., the Minus World is accessed the same way, but is very different in design. World -1 is just like World 1-3, but with underwater gameplay (despite lacking actual visual water) and featuring bizarre elements such as multiple floating Princess Toadstools and a floating (headless) Bowser, as well as an overall glitchy palette for several objects.

It marks the only instance of an underwater flagpole (sans the flag), which can easily be swam over if touched too high; if touched halfway down or lower, however, this flagpole will actually take Mario to World -2, a level identical to 7-3. There is finally a World -3 after this level; -3 is a version of World 4-4 that lacks its False Bowser and maze elements, is colored differently, and is filled with flying Bloopers that can be stomped. (Though intentionally-programmed Bloopers nearly identical to this would be featured in Super Mario Bros.: The Lost Levels.)

Beating World -3 takes the player to the title screen as if the player had beaten the game. If the player starts the game again after going through the Minus World, it will replace all Goombas with Buzzy Beetles and will be like Mario's second quest. Touching any of these flagpoles and generating a fireworks display will stop the game from progressing. When all enemies in World -1 are defeated game will crash as soon as players are close to flagpole at end of this level.

Japanese version of Super Mario Bros.
The American and European versions have one level that loops on forever, while the Japanese version has three-all of which return to the title screen as if the player has beaten the game.

Super Mario Bros. on the Wii
The Super Mario Bros. that is available for download off the Wii's Virtual Console is an exact copy of the original game, meaning that gamers can once again enter the Minus World.

All Night Nippon and the Lost Levels
By using the same trick in All Night Nippon Super Mario Bros. or Super Mario Bros. 2, it will take Mario to the room where the player should get out of the pipe at the end of the level, where the player comes out of a pipe and sees the stairs and the pole.

"Removed"
The Minus World glitch has been "removed" from remakes of Super Mario Bros.. In Super Mario All-Stars, if the trick is performed, the Warp Pipe will still take Mario to 4-1 as if the pipes were gotten to by walking along the ceiling. In Super Mario Bros. Deluxe, the ability to perform the trick is unavailable.

Using hacking tools
If one is to use a gaming tool that can set the level that Mario is on, the Minus World goes all the way to -8. These levels are very strange and may have been used as test levels when the game was being developed. Specifically, World -2 is a version of 3-4 with water graphics; world -3 is a version of 3-4 with overworld graphics, and world -4 is just a blank screen.

As shown in some editor utilities, the first warp zone that can take the player to the Minus World initially loads the data for the second warp zone, which normally only has one warp pipe in the center, until the "Welcome to Warp Zone!" message appears. The two empty slots on the left and right sides would normally read "36" should a graphic of that number alone exist. If two additional pipes were added in the appropriate places in this Warp Zone, they would be sent to the Minus World without executing the glitch. This explains why the second pipe, if the player performs the glitch, takes the player to World 5 instead of 3.

Trivia

 * In Super Paper Mario, The Underwhere is called "World -1" by its residents.
 * Also, in Super Paper Mario, there are three pipes in a secret room in the underground section of 3-1, referencing the way to enter the Minus World (as well as the warp zone).
 * The Donkey Kong Country 2: Diddy's Kong Quest manual's description for Minus Barrels makes a Minus World reference by jokingly attributing them the ability to send the player to the Minus World.
 * On Smash Bros. DOJO!!, when demonstrating how to send Target Smash! videos, one of the Wii Friends was called "World -1.".