Mammoth Cave in Utah is a very interesting place. The short version is that it is comprised of two intersecting lava tubes that form a rough X. It collapsed almost at the dead center of the X and that is how one accesses it.

There are four chambers with one having a metal grill to keep people out during certain parts of the year in order to protect the bats that live there.

Speaking of bats, once I was a good ways into the south cave, there were at least a hundred bats in the ceiling crevices.

The bat's made quite a din of squeaking, and once I had explored all of the caves, I had my dinner above aground, took some pictures and waited for the bats to come out.

They never came out, I think it was just too cold for them. Once it got dark enough to need a headlight, I walked back to my truck and cooked my dinner over a campfire.