[2020] Geography and history

VaMei has the right of it: within the world bands there are an unlimited number of planets. These worlds are broken into islands that can be traveled between via Runegates. The individual worlds are where you'll play Campaigns, set up Eternal Kingdoms, etc. They have as much backstory as we can implant via environmental storytelling and the like, and there are some worlds that have been named in the lore (like the Centaur home world: Pelion).

As to countries, cultures, languages, etc: being that there are a plethora of different worlds inhabited by a number Races that have variations in their own cultures, I'm sure these are as diverse as you can imagine.