Making waves, 140ft below ground in Tennessee Beneath the Smoky Mountains you’ll find the Lost Sea, the largest underground lake in North America. The cave is in Sweetwater, Tennessee which is about 45 minutes from Knoxville and an hour from Chattanooga. Tours last about one hour and include a 20 minute walk each way through the cave before hopping on a 10 minute boat ride across the turquoise lake full of massive rainbow trout . Tickets are about $30 for adults and $17 for kids, and the cave stays a cool 58°F year round (although it felt warmer to me due to the humidity) so bring a jacket! Things to do in Tennessee | Things to do in Knoxville Tennessee | caves in Tennessee #thelostsea #knoxvilletennessee