World 8-3 (Super Mario Bros.: The Lost Levels)

World 8-3 is the third level of World 8 in Super Mario Bros.: The Lost Levels and the thirty-first level overall in said game. The fortress walls in the background appear in the original and Super Mario Bros. Deluxe versions of the game with items being found in Brick Blocks, but the walls are absent in the Super Mario All-Stars version, with items being found in Hidden Blocks. Additionally, this is the only level in the game that takes place entirely in the sky.

Layout
The player starts before a platform that will fall once the player jumps onto it, followed shortly by a Lakitu. Jumping onto the higher platform, the player then needs to jump down onto a Springboard below to cross the next gap, landing on another falling platform. On the next stretch of clouds, the player will encounter Koopa Troopas, Hammer Bros., and blocks containing Poison Mushrooms. Above the second Hammer Bro. is a block containing a power-up and another block to the right containing a Beanstalk leading to Coin Heaven, which will drop the player at the end to just after a pipe with a Piranha Plant shortly after the second Hammer Bro. After the pipe is a block containing a Super Star, and the player must use the Springboard afterward to cross the next gap, which has Koopa Paratroopas flying above it. The player will then encounter two Hammer Bros. before reaching a scale lift, which the player needs to use a block and a running jump to reach. Afterward is a small platform followed by a Koopa Paratroopa and the Goal Pole.

Glitch
In at least the Super Mario All-Stars version, if Mario or Luigi spawns another powerup item/Poison Mushroom after revealing the Beanstalk, the Beanstalk will turn invisible, but remain tangible.