The Farplane

From monuments placed around the world, Rain and the gang can travel to a completely different world.
This area can also be accessed via the icon in the upper right hand corner of the dimensional vortex screen.

These include:

The Farplane, an area with NPCs who can give you useful information. You can access it from each town.
The Dimensional Vortex, a portal which leads to special dungeons you can try. You can access it from the Farplane or the Home screen.