World 2-1 (New Super Mario Bros. Wii)
From the Super Mario Wiki
World 2-1 is the first level of World 2 in New Super Mario Bros. Wii. This is a desert level with Sand Geysers consisting of only one room; no secret rooms are present. Boomerang Bros make their only appearance here. All three Star Coins are in plain sight and accessible using the geysers. This level is not required to progress in the game - completing either World 2-1 or World 2-2 unlocks World 2-3. This is the first level to feature the Desert Theme.
The level starts with a Koopa Troopa walking off a platform onto a Sand Geyser toward the player. There is then a series of four sand geysers; the last is directly below the first Star Coin. After this is another sand geyser and a Brick Block containing a 1-Up Mushroom. Next is a section with geysers and a red Warp Pipe continuously spawning Goombas. There are more geysers, a Boomerang Bro and the midway point.
Continuing forward there are more geysers, this time guarded by Koopa Paratroopas, as well as Piranha Plants on several of the main platforms. The second Star Coin is in a small indentation in one of the platforms. A section with many Piranha Plants follows; one plant is elevated occasionally by a sand geyser and needs to be dodged. Following more geysers, the third Star Coin is obtainable by jumping on a red Paratroopa and throwing the shell, or by using a Propeller Mushroom. After this, there are more geysers, Koopa Paratroopas and a second Boomerang Bro guarding the Flagpole.