World 6 (New Super Mario Bros. Wii)

World 6 of New Super Mario Bros. Wii is a mountainous area featuring many cliffs and rock structures. There are eight levels in this world, two of them being castle levels that are guarded by Morton Koopa Jr.. Various Mushroom Houses are also found around here, giving the player items such as Starmen, Mushrooms, and Propeller Mushrooms. On the map, there are Bullet Bill Blasters which continuously fire Bullet Bills. Mario and the gang can get attacked by them and be forced to play in the Enemy Course.

6-1 Spike Mountain
This level is pretty tough. There are ledges, rock climbing walls, Stone Spikes, and Bullet Bills here.

6-3
In this level, there are Mega Piranha Plants, Stalking Piranha Plants, and Buzzy Beetles. The level is an underground area with rasing and lowering things which the mega piranha plants are on top of. When you see a pasageway that is blocked by brick blocks, break them and wall jump to get a Star Coin.

Enemy Course

 * Infinite Bullet Bills

6-6
In this level, there is a secret exit. To get to it, first use the boat to get to two Fire Bros. Then jump off the boat onto the rock between the two Fire Bros. Then jump on the rock above and you'll see a red pipe. Get into it and pass all the enemies. It will be dark so grab a Glow Block. Once you see a green pipe, jump in and grab the red flagpole. You'll get access to world 6 canon, which will blast you to world 8.

6-Airship
This level has the first appearance of Rocky Wrenches and the Hero Car. This is also where you fight Bowser Jr. for the second time.