This weekend I went to Fisher Cave, one of the attractions in Maramec State Park. (To really confuse people there's a lot of things named Meramec in this area, all with different spellings. This is the one run by the Missouri DNR). Unlike many caves this one is left in a near-natural state. No lights, and we're careful going through not to step on any of the wildlife such as salamanders or disturb the bats. There were several still in hibernation, and they would have a delayed reaction if touched or prodded, moving something like 8 hours later. The railings and walkway were put in by the Civilian Conversation Corps in the 1930's, and are the only man-made things in the cave. I was careful not to use my flash anywhere near the bats, but in open/vacant areas it was fair game. I used my Tokina 12-24mm ultrawide and my SB-600 flash, and most of the time was shooting blind; the only other light was the little LED flashlights we carried. This particular room was the turning around point. A much larger room (two football fields long) was further ahead, but would require going through a flooded passage with barely enough room to keep your head above water--that wasn't part of the regular tour. In the distance I kept thinking the flash was too weak and noise was overtaking the picture, until I noticed it only appeared in some of them; the rooms were large enough they had fog in them. Overall it was a very interesting tour, and radically different from the commercialized caves with all the mood lights.