World 7-2 (Super Mario Bros. 3)
From the Super Mario Wiki
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This level is split between above ground and underground areas, with the player starting above ground next to a Nipper Plant. Up ahead are two ? Blocks, with the left one containing a power-up that can be collected by throwing an Ice Block into it. By going down the second Warp Pipe, the player can enter an underwater area, where they can find a P Switch, Coins, and Brick Blocks to the left. Swimming to the right and entering the far pipe, the player will enter an area with a Koopa Paratroopa and many invisible Note Blocks that the player has to hit in order to create a bridge, along with another power-up at the end of the pipe to the right. Moving back down the pipe the player came from, the player then needs to enter the pipe immediately to the left and use the Note Block bridge to get across, which has a hidden 1-Up Mushroom above it. Immediately after the bridge is a long Warp Pipe that the player can take to find a power-up at the end of a long hall. Continuing on above ground and avoiding the Venus Fire Traps, Piranha Plants, and Nipper Plants, the player should take the fourth to last Warp Pipe to reach the goal.