World 8 (Super Mario Bros.)
From the Super Mario Wiki, the Mario encyclopedia
World 8 is the eighth and final world of Super Mario Bros. In World 8, three ground levels are traversed, as well as the final castle level, which has an underwater section. World 8 is the only world in Super Mario Bros. without any checkpoints; the player is sent to the start of the level if defeated.
Level maps (All-Stars version)