The most chaotic dimension on record, there are almost no safe places here. The Dark Lord Pheonix's everlasting grip wreaks havoc, and if he's not stopped, the dimension's dark infection could spread to the other worlds, taking them over and turning inhabitants into Shadow Monsters or, on rare occasions, Fusion Monsters.
The heart of The Resistance. It has many smaller branches around the globe, called Sunspots for an agreeable reason - the bright, blue force field encasing them makes it highly noticeable, standing out from the rest of the Black Shadow Lava covering the world.
In Sonic Chronicles 3 Dimension Dynasty, Sunspots are safe spots to buy stuff, heal your team, switch team members and make other preparations.