The art museum of Chicago keeps storage at an old nuclear bomb shelter in northwest Illinois. I happened across it reading meters about 10 years ago. I only ever found one other underground facility reading meters, and that was somewhere near the Illinois/Wisconsin border. The entrance looked like one of the buildings Luke Skywalker grew up in. The owner had even built a guard shack next to a cattle fence, complete with a fake security guard and a CCTV camera. The owner probably had a hundred acres of land, and there were barns on the property (with more cameras), but no visible house. Kind of creeped me out really.