We would have dungeons with a similar nature. Ah, all the atrocities and horrors one could do in the dark behind everyone's eyes and ears.

[Richard pressed his front against Silco's, closing the small gap between them so that they could feel the body heat to radiate from one another. His fingers spider walked from the collar to loosely wrap around the silken cravat. He then cranes his neck up, lips just shy away from touching the tip of the older man's jawline. The hold isn't strong nor is he trying to pull him down to meet him, but there definitely is possessiveness and control present.]

Your very own city, then. Who would live there? Who would govern the underground?