World 1-4 (Super Mario Bros.: The Lost Levels)
From the Super Mario Wiki, the Mario encyclopedia
World 1-4 is the fourth and final level of World 1 in Super Mario Bros.: The Lost Levels, taking place in a castle. This level was a part of VS. Super Mario Bros. as World 1-4 and was imported into Super Mario Bros.: The Lost Levels.
The player starts on a path with a Fire Bar at the end above. The path ends at pillars within pits of lava, with the second pillar having the only ? Block with a power-up above it. After three more Fire Bars is a large pit with a set of stairs on the other end, leading to a narrow hallway with Fire Bars and a Koopa Troopa. The hall ends at a pit of lava with the platform on the other end having a Fire Bar. After crossing some more pits and pillars while dodging incoming Fire Breath, the player will arrive at the Fake Bowser.