If you would like to beat summer’s heat by going underground, Tennessee may be your best destination. The state is known for hills and the Great Smoky Mountains. With nearly 10,000 caves under the hills and mountains, you will have lots of spelunking (cave exploring) destinations to choose from; Tennessee is the most cavernous state in the US. The majority of the caves are located in eastern Tennessee, near the Appalachian range. However, many are on private property and inaccessible to the general public.

Among the caves open to visitors are:

1) The Bell Witch Cave ~ a privately owned cave where tours are given during the summer months and in October

2) The Cumberland Caverns ~ with nearly 30 miles of caves and underground passageways, this cave system offers daily walking tours as well as overnight adventures.

3) Raccoon Mountain Caves ~ Visitors here can choose between a 45-minute guided walking tour of Crystal Caverns, or a “muddy” tour of Wild Cave. (The latter requires helmets, pads and gloves; probably not for beginners.)

4) The Lost Sea (In photo) ~ experience the largest underground lake in the US. The guided tour begins with a 3/4 mile walk along sloping paths, down to the lake itself. Then visitors board a glass-bottom boat to explore a bit of the lake, though not the entire 13 acres.

Tennessee, Alabama, and Georgia are known collectively as the TAG cave system; Between them the 3 states have about 14,000 caves.

More Info: whatstates.org