Tunnel leading into the cavern.
Lost Sea Adventure is a cavern located in Sweetwater, Tennessee. It's unique in the way that it has an underground lake that you get to cruise around on in a glass bottom boat. The caverns stay a chilly 58 degrees year round and the water 56 degrees. They brought in some rainbow trout to live in the water but there isn't any food sources for the fish so they have to feed them when they take people out on the tours. Crazy. While we were out in the boat (it does have a very small area that is glass bottomed but the glass was filthy underneath and we couldn't see anything through it at all) the guide told us of a story about one of the fish jumping in the boat during a feeding and Harper was not thrilled about that at all. He was absolutely terrified that a fish was going to jump on him and he worried the rest of the time we were on the water.
Taken just after the boat ride.
I don't think I'd recommend driving 2 hours for these caverns, but it was a good way to kill time. I'm not a huge cavern fan but I think I'd recommend going to Luray over these. The "lost sea" aspect wasn't nearly as cool as it seems like it should be and for the length of time it took to get there it just didn't seem worth it.