World 1 (Super Mario Bros.)

World 1 is the first world in Super Mario Bros. Like all the other worlds, World 1 contains four levels.

World 1-1
World 1-1 is the first level of World 1. It mostly is above ground. There are several pits and pipes, one of which leads underground. At the end of the level is a staircase made of blocks and a Flag Pole.

World 1-2
World 1-2 mostly takes place below ground. There are several pits and pipes. One of the pipes leads even further underground, and another pipe, which is at the end of the level, takes Mario above ground.