World S

World 7 : 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 seven galaxies the last of which, Grandmaster Galaxy, can only be accessed by taking all the 120 Power Stars and the 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 here 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 2 regular levels, and all but one have two Green Star levels.
 * Also, every Galaxy's second level is a Pranster Comet level.