World S

World S: Here We Go!, also known as Special World, is the seventh world featured in Super Mario Galaxy 2. It is located in the sky of an unknown planet with star-shaped continents. It holds a total of seven galaxies, the last of which, the Grandmaster Galaxy, can only be accessed by collecting all 120 Power Stars as well as all 120 Green Stars.

Galaxies

 * Mario Squared Galaxy
 * Rolling Coaster Galaxy
 * Twisty Trials Galaxy
 * Stone Cyclone Galaxy
 * Boss Blitz Galaxy
 * Flip-Out Galaxy
 * Grandmaster Galaxy

Trivia

 * Almost all the galaxies in this world are references to other Mario games.
 * The placements of the seven galaxies form an 'S', hinting at the name of the World.
 * This is the only World in the entire game that every galaxy has two regular missions, and all but one have two Green Star levels.
 * The music for this world is a remix of Gusty Garden Galaxy's music (the galaxy from Super Mario Galaxy).