World 6 (New Super Mario Bros. Wii)

World 6 (NSMB WII) is a tall mountain-themed world in New Super Mario Bros. Wii. The world has many Bullet Bills that are shot from Bullet Cannons in most of the levels in this world. These Bullet Bills also are shot around in different directions on the map itself. Being hit by one on the map means you will have to accomplish a mini-game mission to get all the Toad Buttons (and every other world has this too).

There is a fortress, just like every other world, that the boss of the world dwells in. If this fortress successfully defeated by Mario and his friends, then the boss will go to the next fortress, which is more like a castle. If the boss is defeated here as well, then the boss is done for good. Although most other worlds are successfully finished at the second fortress (or castle), this world's castle is not the very end of the world but instead the second to last level in the world. The very last level is higher in the sky the earlier levels. This can be noticed because you can see that you are above some clouds, and right under others.

At the end of this level, there is another boss battle. The boss is the well-known Bowser Jr. which challenges Mario and his friends by getting them in propelling and flying robots. On each sides of the room are powered-up electric bolts. If Mario or any of his buddies get bumped into them by Bowser Jr, they're dead. But if Mario or any of his friends bump Bowser Jr into a bolt, Bowser Jr. loses some of his health. After 3 hits, Bowser Jr. will be defeated and Mario and his buddies will move on to World 7 (NSMB Wii).