A cave system whose roof fell in, leaving the passages open to the sky
A forked canyon near Thayer that is not really a canyon at all: it is what was left when an ancient dolomite cave system collapsed in on itself. The roof came down and the passages became open-air chasms. The conservationist Leo Drey bought the ground before it came into the state park system, and the 322 acres are privately owned, publicly accessible and run by the Missouri Department of Natural Resources, which is an unusual arrangement for an unusual hole in the ground.
Other places on the map within a couple of hours of here.
