About an hour west of DC is a small cave complex near the VA Skyline Scenic Parkway. It's called the Skyline Caverns. (It's about an hour north of the Luray Caverns)
Right inside the enterance, there used to be a fireplace built into the side of the enterance where they use to have a fire burning to warm those wating to start the tour. They sealed it up as it was allowing non-paying squirrels and skunks in!
Looking down to a pool of water through a crevass.