thanks for the comments! i'll put a black blur behind all the tunnels when i'm done with layout. before then, i'd like to add a few smaller towns, ten more points of interest, and extend the network of connecting tunnels. the blue lines are rivers, i haven't decided if any will be named specifically.

there are two islands of rock in the cauldron. the smaller one near new mechanus i've already assigned as a port for airships, connected to the town by a long iron bridge suspended from the ceiling by chains. the larger one? dunno. i don't think it would be inhabited, but maybe a column of rock with carved facades and abandoned halls. something like Gar Morra from the D&D 4e Underdark book, which i never got to use in my 4e campaigns.