World 3-6 (Super Mario Bros. 3)
From the Super Mario Wiki, the Mario encyclopedia
World 3-6 is the sixth normal level, and the seventh level overall in Water Land from Super Mario Bros. 3. It is unlocked by clearing World 3-4 or World 3-5, and its own completion unlocks World 3-7 (as well as World 3-8, but only if the drawbridge between the two levels is lowered).
This is an autoscrolling level, Mario starts on a platform with some bushes. Slowly, some Donut Lifts appear, along with a ? Block containing a power-up. Afterwards, there is a Rotary Lift, followed by some platforms with Donut Lifts, and a Koopa Troopa. After this, there are more platforms with Donut Lifts, Koopa Troopas, an Ice Block and a Brick Block with another power-up, followed by a Koopa Paratroopa and some platforms with more Brick Blocks containing coins. Next are more platforms with three more Ice Blocks, and Brick Blocks containing a 1-Up Mushroom and a Switch Block, along with a Koopa Paratroopa, another Rotary Lift and a Warp Pipe leading to an area with a single Koopa Paratroopa and the goal.