World Coin-1 (New Super Mario Bros. Wii)
From the Super Mario Wiki
This level starts off with an area resembling the stage from Mario Bros., containing Red Koopa Troopas and a POW Block. Two of the Brick Blocks also contain Super Mushrooms. None of the Brick Blocks can be shattered in this area, and instead simply turn into Empty Blocks. Going through the pipe above takes the players to another area, where there are two more POW Blocks along the way (required to get the other Star Coins), an area with Firebars, Koopa Troopas, and the flagpole.