Chicagoland locations with lots of game potential.

[Chuck Chuck Razool]

I like the Robbie House
en.wikipedia.org/wiki/Robie_House

Designed by famed architectural madman Frank Lloyd Wright, it's just shy of 100 years old and served as a seminary dormitory for 15 years. In addition to this the seminary school wanted to tear it down to put in a more traditional (and functional) dorm structure, but after several years of legal battles it was designated a historic landmark putting the Kai bosh on that.

Huge and maze-like? Check.
Sordid past involving the clergy? Check.
Gunfire and demon summonings? Only a matter of time.

[Vijay]

I agree.  There's already a children's book taking advantage:  "The Wright 3" by Blue Balliett.