Greyhawk - The Planes of Oerth

Introduction

Oerth's Immediate Environs

Luna

"For instance, suppose that you decide that there is a breathable atmosphere which extends from the earth to the moon, and that any winged steed capable of flying fast and far can carry its rider to that orb.  Furthermore, once beyond the normal limits of earth's atmosphere, gravity and resistance are such that speed increases dramatically, and the whole journey will take but a few days.  You must then decide what will be encountered during the course of the trip--perhaps a few new creatures in addition to the standard ones which you deem likely to be between earth and moon.

Then comes what conditions will be like upon Luna, and what will be found there, why, and so on.  Perhaps here is where you place the gateways to yet other worlds.  In short, you devise the whole schema just as you did the campaign, beginning from the dungeon and environs outward into the broad world--in this case, the universe, and then the multiverse."

Celene

The Inner Planes

The Outer Planes

• The Nine Hells

• The 666 Layers of The Abyss

The Demi-Planes