Last October while we were in the Dubuque area, we stopped at the Mines of Spain State Recreation Area and E.B. Lyons Nature Center.  The nature center was a sort of small museum with a gift shop and a conference room.   A field trip for an elementary school class seemed to be in progress; there were a lot of children.
We started our hike on the very short Pine Chapel Trail.  The roof of the chapel was being fixed, and a local historian happened to be there.  She told us about the chapel, built in the 1860s by Otto Junkermann to resemble a church he remembered in Germany.  It seems this chapel, though, was never really used as a church.