Editing The Wyzard Setting Essays (section)

==Geography==

===The Hollow World===
Scholars, of course, know that there is no hollow world, and that the entire business results from drastic misapprehension and ignorance.  

It is indeed possible for those who are willing to brave the dangers of extended travel through vast, uncharted caverns in the world (and the unspeakable creatures, forgotten by the light of day, which inhabit them) to come to a strange and entirely different planetary surface, which sits under a different sun and different stars.  The people of that sphere, of course, insist that their own sphere is the true one, and that the world of the traveler is in fact the hollow world of their own planet.  Both the native and the traveler have committed the fallacy of dimension-centrism.  In fact, it is the same planet, but with two different surfaces areas in alternate areas of spacetime.  The tunnels are those places where the (contiguous) surfaces wrap in and around four-dimensional space 

It will be most helpful to picture the arrangement as a Moebius Strip, or more accurately as something like an arrangement of interlocking Klein Bottles.  Or, perhaps, that won't be helpful at all.