Pic: Limestone formations. Lewis & Clark Caverns SP, MT
Lewis & Clark Caverns State Park contains a show cave with all its associated bright lights and metal railings. Thanks to some internet sleuthing and lucky timing, however, I took the more intimate “wild cave tour”. Equipped with helmets and headlamps, overalls and kneepads, ten of us toured the cave like actual spelunkers. With the overhead lights off (except to allow the above picture), we squeezed and crawled through areas not ordinarily seen by the public. We saw soda straws and cave bacon and even a couple of bats sleeping on the ceiling.
Derrick, the ranger who established the program in 2015, was a terrific and knowledgeable guide. 5 stars, would wild cave again.

Pic: Good advice in almost all situations. Lewis & Clark Caverns SP, MT