The Tallest Underground Waterfall You Can Visit in the U.S. Is Hidden Inside This Tennessee Mountain

The South is filled with natural wonders, from dramatic gorges and massive cave systems to beautiful wetlands and pristine beaches. If you find yourself in East Tennessee, specifically, you’ll be within driving distance of the incredible Great Smoky Mountains National Park, America’s largest underground lake (The Lost Sea), and a waterfall known as Ruby Falls.

Ruby Falls isn’t your ordinary waterfall. “The most notable difference is that the Ruby Falls waterfall is underground,” says Hollie Baranick, the tours and guest experience manager at Ruby Falls. “There are not many other underground waterfalls that are so easily accessible to the public.”

Located more than 1,000 feet beneath the surface of Lookout Mountain, the towering waterfall was discovered by chemist Leo Lambert and his crew in 1928 while building an elevator shaft that would provide access to Lookout Mountain Cave. The cave had been used for centuries, but had become blocked when a train tunnel was built through Lookout Mountain. Lambert named the falls after his wife and high school sweetheart, Ruby Losey, and the first public tours were conducted in 1930.

Today, travelers come from near and far to take in this magnificent scene, as well as the jaw-dropping views from Lookout Mountain, the history of the destination, and a plethora of other interesting things to see and do. Here’s how to plan your own Ruby Falls visit.

What to Know About Ruby Falls

“The tour starts at the elevator, which takes you 260 feet underground into Lookout Mountain. The elevator has a glass door, so you can see the rocky mountain walls while going down,” explains Baranick. “From there, a tour guide walks you through the cave, starting with a stop that explains our unique history, including how Ruby Falls was accidentally discovered! Your guide will point out some of the formations and the imaginative names we’ve given some (like the ‘Fish’ formation, named because it looks like a fish).” She shares that her favorite stop along the way is the Hall of Dreams: “If you look up, the whole ceiling is covered in stalactites. It’s amazing.”

Of course, the real show occurs at the falls themselves. “When you enter the Falls Room, it is very dark with only floor pathway lights. Once everyone is close to the waterfall, the lights turn on in a dramatic reveal,” she says. “I’ve seen the light show hundreds of times, and that never gets old.”

There are several different tours you can take, including an after-hours lantern tour, an adults-only cave walk, and a geology tour. No matter which one you choose, be sure to heed Baranick’s advice. “Don’t forget to look up and down! Because of the layers of rock, there are neat little pockets where you can see streams from the waterfall,” she says.

She also recommends buying your cave tickets as soon as you can—and giving yourself plenty of wiggle room in your itinerary.  “I don’t think guests realize how many times our tickets sell out. I’ve seen groups wait for hours for an available tour or not be able to tour at all,” she says. “And plan to be a little early, so you have time for parking and restrooms before the tour. If you miss the tour, you may have to wait a while until there is a spot on another tour.”

Other Things to Do on Lookout Mountain

“A lot of guests look for a specific attraction called Lookout Mountain. What they don’t realize is that Lookout Mountain is the name of the whole mountain, and there are lots of things to do up here,” Baranick explains. “All the attractions up here are proud to be on Lookout Mountain, so we all use the term. It can be confusing sometimes for our guests.”

While you’re visiting Ruby Falls, you could check out the panoramic views from Lookout Mountain Tower, get a bite to eat at the historic Ruby Falls Castle, and sail through the treetops at High Point ZIP Adventure. “Of course, the other main attractions include Rock City and the Incline Railway,” she adds. “I would personally recommend checking out some of the hiking trails on the mountain, or if you are daring, the Lookout Mountain Flight Park for hang gliding!”

Best Time to Visit

Ruby Falls is also remarkable in the fact that there’s really no bad time to visit. “Since we are underground, you can visit even when it’s raining,” says Baranick. “We are also ideal to visit when it’s hot or cold outside—the rocks are good insulators in the cave, so it stays 60 degrees year-round.”

That said, the holidays at Ruby Falls tend to be pretty amazing—she notes there’s “always a magical feeling with the lights and decorations on the castle”—but she also recommends timing your visit for the early morning or late evening. “During those times, most of the crowds have gone away (unless it’s a holiday weekend), and the tours are often smaller and more intimate. It’s a special time of day,” she says.