Huntsville Cave, does it really exist?
Article Excerpt: "by Joy Russell... the backhoe bucket broke through the ground into the tunnel, steam came up out of the tunnel for about an hour. He felt this steam was caused because the temperature inside the tunnel was warmer than the air temperature. When the tunnel filled with cooler air, the steam stopped and the crew stuck their heads down into the hole and looked into the tunnel with their flashlights. The tunnel ran as far as they could see both to the North and South and the floor of the tunnel was located about 8 or 9 feet below the surface of the ground. According to Howard and Dixie Cain, there were several dumptrucks full of gravel dumped into it but this didn't begin to fill it up. The utility company finally placed a large metal pipe across the hole and ran their pipes inside of it and were able to cover it this way ..."
Reference: files.usgwarchives.net