If you like everything prehistoric, which I do, this is your place. The Black Hills Institute in Hill City, SD has a large collection of cast replica dinosaur bones, fossils, fish and sea creatures as well as minerals and rocks all in one place. And while it isn’t very big, I found we spent a ton of time there just LOOKING at everything. My daughters loved digging up bones in the sand table. It keeps the little kids busy while you get to stroll around museum. Also kudos to the staff for choosing great music to listen to as well. It was surreal listening to Nora Jones while looking at a T-rex! This is also the place that I think I took the most photos.