The Lost Sea is the largest underground water feature in the world, or so they claim. I have never looked it up to see if it is true. The Sea, or lake, is 4.5 acres in size and is very clear. They stock rainbow trout in it which have become so tame you can touch them in the water as you cruise around in glass bottomed boats. Access to the lake is through a 1/4 mile guided tour down a cavern, complete with several cheesy jokes and puns. Overall it takes about 90 minutes for the tour down, the boat ride, and the climb back out.
We had a lot of fun, and watching Nora amazement and wonder in her eyes was worth the price of admission alone. I don’t want to give away any details as that might ruin the experience a bit. But one detail that always stuck with me as a child was the water fountain in the gift shop. I recall making my parents buy me a cheap canteen in the gift shop so I could fill it from the fountain, which was reportedly water that came straight up from the lake. So when we got to the gift shop the first thing I looked for was that water fountain. And sure enough, I was correct, it was there, and it was fed from the lake below. The only thing I found out is that the water is filtered before getting to the fountain, which is probably a good thing, just not how I remembered it.
Overall for the price, the Lost Sea Adventure is worth it. It is a piece of Americana that should be checked out if traveling through Tennessee on I-75, especially if you have kids. It is always a constant temperature of 58 degrees, open rain or shine, all year round, and gets them good exercise to help get energy out to make being stuck in a cramped car easier.