I was writing a quick note for my world when the idea struck me for an aptly-named challenge - mapping that which cannot be mapped. here's the quick note i came up with:
Batep, the lost-plains: This sun-drenched land is tainted by Firmamental forces, rendering travel disorienting and navigation near impossible. Theair itself seems alive with illusory shimmerings, akin to desert-mirages, though afflicting the entirety of the region. As though the blindness from the white-sands and salty desert were not enough to deter exploration, time and distances itself seem mutable in this place - a journey between cities might take a day one way and weeks the other. People can wander for months without ever encountering sign of civilzation. Water here is a rare and valued commodity. Little exists in those bleached wastes, though ruined echoes of ancient towers remain, each topped by archaic refractive engines though to either be the cause of this strange geographical malady... or perhaps a long-forgotten solution. Few who come across these ruins can pinpoint their location and indeed any form of cartography in these lands is impossible, the various attempts at mapping the region making madmen of cartographers.
that last line has me grinning - are there any cartographers here willing to try and map the impossible?
NB: the text block was only a bit of fluff - any theme or idea can be used, as long as its an attempt to map that which under normal circumstances might be considered unmappable