When Random Wizard made public a map of the infamous Michigan State steam tunnels -- implicated in the sad case of James Dallas Egbert, later fictionalized in the novel and TV movie Mazes and Monsters -- I had my raw material, and my inspiration. The dungeon map reconstructs them circa 1980.
|Click to enlarge; edited from first post.
Remember, it's not satanic if they're not called demons and devils! (I always liked Knights of the Dinner Table's take-off on that - "we'll call them ne'er-do-wells.")