Alley Spring. I don't know anything about the history of the place. Very relaxing, once there, but it's a roller-coaster ride to get in and out.
That picture faces the spring, but you can't see the spring in the picture. There is a large pool behind the mill, and the spring feeds the pool. The caves on one side of the pool weep, but the caves on the other side are dry.
The water where I was standing when I took the picture was probably about 60 degrees, which seemed warm, compared to my expectations.
