Sometimes it can seem as though everything has been done for outdoor enthusiasts—every trail has been traveled, every peak has been climbed, and now you’re thinking about taking up an indoor pastime like knitting. But wait! Now might be a good moment to think about going underground rather than climbing mountains.
There are literally endless underground tunnels accessible for you to enjoy, assuming you’ve defeated your fear of darkness and your claustrophobia. There are approximately 45,000 caverns in the continental US alone, including the largest cave system on earth. We’ve chosen some of the most intriguing caves in America, many of which are just waiting to be discovered. Do not watch “The Descent” prior to going spelunking. Have a great time!
#1 Mammoth Cave (Kentucky)
With 400 miles of excavated caves, this UNESCO World Heritage Site has the longest cave system on the entire planet. The year-round selection of beautiful routes includes both professional and self-guided trips, with levels of difficulty ranging from fairly straightforward to extremely challenging.
Each of the many guided tours covers a few of the cave’s most recognizable features: you can visit the underground river on the River Styx Tour, explore rock formations that replicate Gothic buildings on the Gothic Avenue Tour and wander by torchlight alone on the Violet City Tour.
Bonus: If you visit during a storm, you might even notice a layer of mist forming inside the cave. Very eerie.
Tour availability varies by season. Children’s tickets cost $9, while adult tickets are $11.
#2 Jewel Cave (South Dakota)
In the South Dakotan Black Hills, there is so much great stuff to see above ground that it seems unthinkable that there is also cool stuff to see below ground. Oh, surprise! A national monument since 1908, Jewel Cave is the third-longest cavern system on the planet, with more than 180 miles of documented and inspected passageways.
The cave lives up to its name, with massive calcite crystals coating the ceilings and walls that resemble dripping jewels (there is also a 10-foot-long chunk of flowstone known as “cave bacon”). Three distinct guided tours through the tunnels are available, ranging in difficulty from easy to difficult.
Each season has a different tour schedule. Scenic Tours is the only one that accepts bookings in advance; all others are first-come, first-served.
#3 Devil’s Den Spring (Florida)
While other caverns have hidden rivers, ponds, or waterfalls, Devil’s Den Spring is a dedicated diving location. It was created by a karst window, which is simply a cave roof that falls down to reveal an ancient underground river. (The final result resembles a cenote.)
With maximum depths of 54 feet and a year-round average temperature of 72°F, the water is perfectly clear and vividly blue, allowing divers to see ancient rock formations and fossil beds that date back 33 million years.
With the right certification, scuba diving is available every day of the week; reservations are not required (if you want to dive at night, you will need an appointment). Every diver needs a dive partner. Each diver must pay $38 to enter, and equipment rentals are available. By appointment only, snorkeling is also offered; entry prices start at $15 per person, and rental gear is provided.
#4 Meramec Caverns (Missouri)
Missouri is referred to as the “Cave State” because there are more than 6,400 caves that have been identified, yet only twenty are open to the general public for guided tours. Because of its location alongside historic Route 66, its reputation as a previous refuge for bandit Jesse James and his crew, and its history as a destination along the Underground Railroad, Meramec Caverns is the biggest and most popular system of the group.
Nowadays, well-lit guided tour roads are flanked with artificial props, neon signage, and mood lighting in a variety of colors. An old limestone structure called the “Wine Table”—which they refer to as the “world’s rarest cave structure”—and a seven-story “mansion” constructed beneath are among the attractions that Meramec’s 150,000 annual tourists may look forward to seeing.
Starting at 9:00 a.m. every day, tours are provided every 20 minutes. Tickets cost between $13 and $24 for adults and children aged 5 to 11.
#5 Luray Caverns (Virginia)
The Luray Caves in Virginia’s Shenandoah Valley are the biggest and most visited caves in the eastern US, having formed some 400 million years ago. An estimated 500,000 people visit the system’s spectacular underground rock formations every year. Guided tours take you through Giant’s Hall, which is advertised as “Geology’s Hall of Fame,” and its impressive Double Column, Dream Lake, Frozen Fountain, Saracen’s Tent, and Titania’s Veil.
The Great Stalacpipe Organ, the biggest wind instrument in the world, is located here as well. Its stalactites are gently tapped by rubber mallets that are electrically controlled, transforming the three acres of rock into a music hall.
Daily tours are available from 9 a.m. to 6 p.m. Tickets cost $32 for adults and $16 for children aged 6 to 12.
#6 Howe Caverns and Secret Caverns (New York)
Howe Caverns and Secret Caverns, two underground wonderlands with gorgeous water features, are both located in the small hamlet of Howes Cave in New York’s upstate. The similarities stop here, however.
In Howe Caverns, visitors can take a boat ride over a subterranean lake’s beautiful, quiet surface, while in Secret Caverns, there is a roaring 100-foot subterranean waterfall. The Secret Caverns offer you a wild and adventurous experience that you will not forget very soon. On the other hand, Howe Caverns provide a more organized experience. Whatever you decide on will be well worth your effort and money, and because they are close to one another, we advise visiting both.
There are many tour options available at Howe Caverns, some of which require advance online reservations. These options include regular tours, expedition tours, and specialty tours with overnight stays. Prices for kids aged 5 to 12 start at $15, while for adults they start at $25. Secret Caverns only accepts cash and offers one basic tour; it also does not accept reservations.
#7 Natural Bridge Caverns (Texas)
Everything in Texas is bigger, as the saying goes. This obviously includes Natural Bridge Caverns, the biggest commercial cavern in the country. Natural Bridge, so named for the 60-foot-long, naturally occurring limestone bridge that spans the area’s entrance, provides a variety of tours, one of which, the Discovery Adventure Tour, will have you crawl through confined areas to view abandoned subterranean rooms.
The world’s largest bat colony is also located here, and tourists can see it in action during the summer when thousands of free-tailed bats exit the cave at dusk to go looking for food every night.
The starting price for children is $14.25, and for adults, it is $21.75 a day, though prices can vary.
#8 Ape Caves (Washington)
The Ape Caves, which run for more than two miles into the earth, were created around 2,000 years ago when Mt. St. Helens erupted. They are the world’s longest lava tunnels in the continental US. The cave is accessible throughout the year, but bear in mind that it typically stays at a comfortable 42 degrees and that water and “cave slime” have made the walls slippery.
The Upper Cave is much more difficult and harsh, requiring you to scale a slippery 8-foot lava fall and squeeze through some small crevices. It is considerably simpler to move around in the Lower Cave, which is a large tube with a level floor and a gentle descent. As you move through the latter, be on the lookout for the structure known as “The Meatball,” a ball of petrified lava rock that dropped from the roof as the tube was building and formed a fairly ominous archway.
Entry is free; however, a Northwest Forest Pass is required to take the self-guided tours. To visit between April and October, reservations are necessary.
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