Our day began in Mammoth Caves National Park, after another thunder storm/deluge in the middle of the night. It's a cool thing they do with their weather in this part of the country. They have these fascinating thunder and lightning storms in the middle of the night that, apparently, can't stand the light of day. While the days seem to have brief deluges they don't last, and the daylight weather has been nice and sunny.We headed over to visitor center and, despite having a strong recommendation to do the "Wild Cave Tour", we signed on for the "Frozen Niagra" and "Historic" tours. In retrospect, Theresa believes she could have done the six hour, belly dragging, wild tour, so we guess we'll be back... The Mammoth Caves, so named because they are huge, were awesome and we will be ever thankful for deep dark cool caverns in this kind of weather. After about four hours below ground, we resurfaced and drove east from Mammoth Caves, along some great rural Kentucky backroads though towns like Beaumont, Knob Lick, Marrowbone, and Static, down into Tennessee. After skirting Knoxville in the late evening, we arrived at the Elkmont Campground in the Great Smoky Mountains National Park for the night.