Preparing my Sandbox experiment, I realized I never posted these maps. That’s a bit weird, because I like the concept.
The Impossible Earth – a working title – was once your average fantasy world, with a huge underworld hidden beneath the surface. One day, the underworld collapsed all over the planet, and in the resulting cataclysm most of civilization was destroyed.
The underworld’s caverns were so large that the world’s oceans were drained into them. In fact, this drain is still going on, with one minor ocean remaining on the surface.
The dark gray areas on the surface map are caved-in areas – here the former underworld is exposed to the sky.
The main layout of the underworld – of course countless smaller caves riddle the seemingly solid areas.
And that is how a composite of surface and underworld looks like.
As always the maps have a discussion forum on the Cartographers’ Guild.
I personally love this concept, and I have never heard of anybody else doing this before. I won’t be so bold as to claim this is a completely new idea of course. At any rate, I’d love to hear what you guys think of this concept!
Edit: Work on this map continues.