World 4 (Super Mario Galaxy 2)

"We've sure come a long way, thanks to your efforts! Let's keep this good thing going, am I right? The helm is yours, Captain!"

- Lubba

World 4: The Many Mysteries of the Cosmos is the fourth world in Super Mario Galaxy 2. It is located near a spiral galaxy/Milky Way Galaxy. It holds seven galaxies, the last of which, Bowser's Gravity Gauntlet, features the second encounter with Giant Bowser, who again attacks Mario on a small planet, though now with several new moves. The Hungry Luma galaxy is available right when the player enters, which does not happen in any other world.