World 7-4 (Super Mario Bros.: The Lost Levels)
From the Super Mario Wiki
The player begins in a narrow corridor with a Fire Bar and a drop down to a pit of lava with a horizontally moving lift. At the end of the corridor is a Hidden Block containing a power-up directly against the wall, followed by a Fire Bar before five rails of downward moving platforms. Afterward is another corridor with a Fire Bar and Koopa Troopas on narrow pillars. The corridor leads into a room with Buzzy Beetles, which leads into another narrow section with Fire Bars hanging from the pillars above. The player then has to traverse platforms over a pit of lava while dodging a Lava Bubble, a Fire Bar, and Fire Breath. At the end of the room is the Fake Bowser, which throws hammers and the bridge has a Fire Bar.