Take an epic road trip to Tennessee’s coolest caverns

Beneath the mossy hills and flat farmlands of Tennessee lies a complex network of more than 10,000 caves. From a subterranean lake so large its full extent has yet to be discovered to the cavern that inspired Johnny Cash to seek sobriety, Tennessee’s underground world is teeming with bizarre legends and surprising sites.

Ready to spelunk? Here’s our guide for cooling off on a 550-mile road trip loop through the underside of Tennessee.

Day 1: The lost sea and ancient cats

From Chattanooga, drive about an hour east to Craighead Caverns to find the world’s second largest non-subglacial underground lake. With more than 13 acres of water charted by divers and an extensive underwater cavern network revealed by sonar readings, the lake’s complete expanse is yet to be discovered.

Take a tour of the cave’s historical highlights, including Cherokee jewelry and pottery, clusters of rare formations called “cave flowers,” and casts of tracks left by a mega-jaguar 20,000 years ago. After a short trek into the cavern, board a glass-bottom boat for glimpses into the underwater world and its hovering clouds of rainbow trout, colorless and blind from ages in darkness.

Overnight: Try the KOA and Notchy Creek campgrounds, or head to the southern Cherokee National Forest to choose from backcountry and developed campgrounds.

Day 2: Supernatural cave art and haunting folklore

About 3.5 hours northwest of Craighead hides a cave more known for its haunting folklore than its geographical qualities. Recognized by the National Register of Historic Places, the Bell Witch Cave was owned by John Bell in the early 1800s. According to legend, the Bell family was tormented by a witch who found sanctuary in the cave after killing John. Today, the privately-owned cave offers tours for visitors to learn about the haunting—considered the country’s greatest ghost story—and to see the lava-like flowstone oozing from the walls.

Related: see more spectacular caves

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Crystal (Un)clear PathSome of our planet’s most massive and difficult-to-reach caves are still in the process of having their secrets revealed. Take a look at a collection of the best photos of these extreme caves recently featured in National Geographic.

Here, massive beams of selenite dwarf human explorers in Mexico’s Cave of Crystals, deep below the Chihuahuan Desert. Formed over millennia, these crystals are among the largest yet discovered on Earth.

—Brett Weisband

Photograph by Carsten Peter, National Geographic

Thirty minutes west of Bell Witch Cave, Dunbar Cave State Park’s guided tours let visitors discover the cave’s Mississippian Native American iconography, dating to A.D. 1350. Carved and drawn into the limestone, figures including concentric circles and a supernatural warrior figure remain a testament to the Mississippian belief that caves were a portal to the underworld.

Overnight: Spring Creek Campground welcomes both tents and RVs—but you might choose to float past the Bell Witch Cave before settling in at Red River Campground.

Day 3: Cavern whiskey and underground bluegrass

Head a couple hours south to Cave Spring Hollow, the spring water source for every bottle of Jack Daniel’s sold around the world. Pulling 800 gallons of water a minute from deep below Earth’s surface, the cave’s limestone removes iron from the water and leaves behind a mixture of minerals. According to Jack, it was the perfect concoction for whiskey-making water.

Following a tour of the Jack Daniel’s Distillery, drive about an hour northeast to Cumberland Caverns. This historic national landmark offers day and overnight tours for spelunkers (both novice and experienced) to explore the cave’s 32 miles of stalagmites, stalactites, and other unique features.

With its exceptional acoustics, Cumberland Caverns has also hosted a variety of musicians for more than half a century in its Volcano Room, hundreds of feet below the surface. And if Cumberland Caverns doesn't satisfy your musical cravings, head an hour south to The Caverns. Home to the Bluegrass Underground, it’s where you can see artists such as Steve Earle, Greensky Bluegrass, and Old Crow Medicine Show pick, pluck, and perform in a subterranean amphitheater.

Overnight: Sign up for one of Cumberland Caverns’ overnight caving and camping adventures, or pitch your tent at a nearby state park or archaeological site.

Day 4: Sunset paddleboarding and Johnny Cash’s redemption

Round off your trek with an hour-long drive back to Chattanooga for a tour of Ruby Falls, the 145-foot-high underground waterfall cascading more than 1,120 feet beneath Lookout Mountain. In the evening, backtrack a half hour west to Nickajack Cave, an important refuge for hundreds of thousands of endangered gray bats.

It was in this refuge that singer Johnny Cash was allegedly “born again” after crawling into the cave to end his life. According to his autobiography, he had a spiritual experience of peace and clarity in the cave’s darkness. Encouraged to find his path to sobriety, he went on to record the famous Live at Folsom Prison album the following year.

Partially flooded by the Tennessee Valley Authority, the cave is closed to reduce the spread of white-nose syndrome, a devastating fungus that can affect hibernating bats. But visitors can still paddleboard across Nickajack Lake to watch the bats fly out of the cave’s mouth each sunset, swooping up their supper of mayflies and stoneflies in the muggy summer dusk.

Overnight: Spend the night in Chattanooga, or set up a tent at one of the area’s many campgrounds, including Raccoon Mountain Caverns and Campground.