Illinois

This is a limestone mine. I have been in a few in the region because some of them have refitted some shafts to accommodate cold storage facilities. It's kind of creepy driving around in them in a semi, it's very dark, only your headlights and whatever else you have and you can hear large machines racing around somewhere but you have no idea where they are. The only way to see the dock you back into is when they open the door so you can see it and the reflecting stripes around it.

There are several in IL, MO and KS.