World 9 (New Super Mario Bros. Wii)

World 9 for New Super Mario Bros. Wii is a rainbow colored star in space. It is technically the last world in the game. The World is a really special world, where you can unlock 8 different levels by collecting all the Star Coins for each world. In the menu where you select the world you want to go to, instead of the world being in a circle like with all the other worlds, it is above the center of the circle.