While you could spend a lifetime exploring the diverse landscapes of Earth’s surface, entering a subterranean cavern opens up a whole new world for the curious traveler. The largest caves in the world provide a glimpse into Earth’s evolutionary past and an eerie adventure into a murky underworld filled with awe-inspiring rock formations, sparkling minerals, and unlit obstacle courses.
For the avid adventurer, exploring a tangle of unknown passageways, traipsing through underground rivers, and rappelling the walls of the world’s deepest caves is a verifiable addiction. Others are content to stroll on the boardwalk in a well-lit tourist structure. Whichever type of traveler you are, we’ve got a magical cavern on the list for you! We’ll take a look at the world’s biggest cave, explore a few U.S. National Park cave systems, and find out which caves are best for touring.
Starting Your Adventure With Let’s Roam!
If you’re looking for some of the largest caves in the world, you’ll want to head for the state of South Dakota. SD is full of fun cities and charming small towns, and we’ve got scores of fascinating scavenger hunts to help you explore in style! Our hunts include fascinating trivia and engaging photo and video challenges to keep the crew on their toes. Download our scavenger hunt app, and check out the full array of South Dakota hunts today!
Exploring the World’s Largest Caves
It turns out that “largest” is a much more difficult word to define than one would initially think. The thousands of caves in the world are classified by length, depth, and overall volume. So, the largest by volume might not necessarily be the longest (it isn’t). Therefore, things get a bit sticky. But our concern here isn’t really the exact size—though we’ll include that, too. We’re more concerned with which massive caves are the best for exploring. With that covered, let’s get to it! Here are the best cave exploration destinations in the world, in no particular order.
1. Hang Son Doong Cave—Largest in the World
Stumbled upon by a Vietnamese resident named Ho Khanh while hunting in the jungle, the Son Doong Cave system was declared the largest natural cave in the world by National Geographic and Guinness World Records in 2013. Though it was initially found in 1990, the hunter didn’t explore it and couldn’t refind the entrance. In 2008, he found the cave again (and noted the path this time) and led two members of the British Cave Research Association to map the system.
It was apparent from the start that Hang Son Doong (”Mountain, River Cave”) was like no other place on Earth. Located in the stunning Phong Nha-Kẻ Bàng National Park, the cave system houses a completely unique ecosystem. It includes underground rainforests, two rivers, two massive skylights, ancient fossils, 90-meter-high walls, massive cave pearls, and towering stalagmites the size of skyscrapers. By volume, the cave is estimated at 38.5 million cubic meters. For reference, Deer Cave in Malaysia was formerly considered the largest by volume at 9.5 million cubic meters.
Vietnam is a paradise for cavers. Aside from Hang Son Doong, visitors can explore the natural wonders of the gigantic and diverse Tu Lan Cave System and the varied caves of Hang Ba Deep Jungle. All of these adventures are available by guided tours from Oxalis Adventures. They offer a handful of tours for adventurers of all experience levels.
2. Verëvkina Cave—Deepest in the World
Located in the Abkhazia region (a Russian-supported separatist region in the Ural Mountains of Georgia), the Verëvkina Cave is the deepest in the world at 7,257 feet (or 2,212 meters) deep. Though it was discovered in 1968, the intricacy of the cave’s interior made it difficult to fully survey. It wasn’t until 2019 that the final numbers came in after a 2018 survey team almost lost their lives to a flash flood while camping at the base of the cave.
While the researchers narrowly escaped with their lives, others were not so lucky. The cave has claimed a few lives, including that of a young Russian adventurer who was found suspended from his gear some nine months after his disappearance. He had ignored all safety warnings and taken on the cave system alone and underprepared. It is thought that he succumbed to hypothermia in the depths.
The cave is not only the deepest in the world, but it contains the deepest known pool, a clear blue swimming hole surrounded by black stone. Much of the rest of the cave is made of sky-blue calcite, making it an awe-inspiring natural wonder. There are no official tour companies descending the cave, and proper gear is hard to come by in the region. Entering Verëvkina is not for amateur or even moderate cavers. It should only be taken on by highly trained teams with top-of-the-line gear and communication equipment.
3. Mammoth Cave—Longest in the World
The state of Kentucky is home to some truly epic caving experiences. Topping that list is the appropriately named UNESCO World Heritage Site of Mammoth Cave National Park. Clocked at over 400 miles (680 km), the cave is the longest in the world by spades. Archeological evidence suggests that humans have been exploring the cave for more than 5,000 years. It is thought that Pre-Columbian Native American groups used the caves for funerary rights. The oldest specimen found in the cave was deemed “Lost John,” and his remains are on display to visitors.
Mammoth Cave National Park offers a series of tour options. Several segments of the system are well-lit, with added staircases and tourist infrastructure. Others are certainly not. Tours range from the semi-difficult “Introduction to Caving” tour, involving climbing and crawling through off-grid parts of the system for 3.5 hours, to wheelchair-accessible tours. Tours must be reserved through the U.S. National Park’s Recreation Website. Outside of the national park, the rest of the state is loaded with spelunking opportunities. From tourist caves like Diamond Caverns to a host of wild caves like Angel’s Pit, Blue Hole, and String Cave, if you have a hankering for subterranean exploration, Kentucky provides a lot of bang for your buck!
4. Clearwater Cave System
Located in Gunung Mulu National Park in the Sarawak region of Borneo, Malaysia, the Clearwater Cave System was discovered in the 1970s. The caverns contain an underground river and span more than 159 miles collectively. The cave has still not been completely surveyed and consists of several interconnected chambers. It’s also considered to be one of the biggest caves by volume in the world.
The Mulu Caves consist of Clearwater Cave, the ninth longest in the world. Deer Cave contains the largest cave passage, and the Sarawak Chamber is thought to be the largest cave room in the world. The Mulu Caves are often contested against Son Doong for the title of largest. Who knows? These measurements drive tourism, are often politically charged, and are notoriously difficult to estimate anyways. What’s for sure is that the Mulu Caves are some of the largest and most impressive on Earth.
Guided and unguided tours of varying levels are available through the national park. It should be stated that Borneo is wildly known for its diverse and stunning landscape. While discovering the caves, you could also check out the Pinnacles hike or summit Gunung (Mt.) Mulu. If you’re a multi-sport adventurer, there’s not really any destination more worthy of your time and effort.
5. Lechuguilla Cave
Lechuguilla Cave is a massive New Mexico beauty that is located within Carlsbad Caverns National Park. It was discovered in the early 1900s but not mapped until 1986. At 138 miles long, it’s the eighth longest in the world. It’s also the second deepest cave on the American continent.
Lechuguilla is also remarkable outside of its size. It’s set apart by outstanding beauty and peculiar rock formations. Unfortunately, Lechuguilla is not open to tourists. However, within the national park, visitors can tour the ethereal Carlsbad Caverns. It doesn’t disappoint either, as the “Big Room” is the largest cave chamber by volume in the U.S. It’s an absolutely gorgeous cave system, with intricately formed stalactites and stalagmites, well-lit boardwalks, and accessibility for all.
6. Wind Cave
Another excellent destination for caving is South Dakota. Wind Cave National Park is home to the seventh-longest cave in the world. Wind Cave is classified as a “maze cave” due to its convoluted series of passageways. In fact, the system has more passages per cubic mile than anywhere else, making it the densest cave on Earth. The cave takes its name from the strong wind gusts that greet trekkers upon entry. It was the sixth national park to be designated in the United States and the first cave to be given that designation anywhere in the world.
Wind Cave is famous for its boxwork formations, thin blades of calcite that hang from the walls and ceilings in a honeycomb pattern. It contains approximately 95% of the known boxwork formations in the world. It’s a truly unique cave for touring. Several guided excursions are available through the National Park Service.
7. Optymistychna Cave
Let’s not leave out Europe! Though it’s better known for its historic cities, fine cuisine, varied landscapes, and stunning cathedrals, Europe can’t be kicked out of the cool cave club. The most impressive on the continent is located in war-torn Ukraine. While that might not top your wanderlust list, we’re remaining hopeful that peace will come to this region soon.
Optymistychna Cave is also a maze cave and one of the longest gypsum caves in the world. At 164 mapped miles, it ranks as one of the longest on earth, and it’s one of the wildest that you can tour. With low passages and bewildering gypsum formations, the cave is a mix of eerie obstacle course and otherworldly palace. In fact, if you didn’t know better, you might feel as if you were on a snorkeling adventure exploring the coral formations of the Great Barrier Reef. The formations are that beautiful and diversified. It only opened to tourists in recent years, and though there are seven guided tour options, it’s still relatively undiscovered by mass tourism. Tours range from 3 to 14-hour treks and encompass a wide variety of difficulty levels!
Fun fact: The cave name translates to “optimistic,” as original surveyors said it would be no more than three km deep, but a group of explorers was “optimistic” that they would find more… and boy did they!
8. The Shuanghedong Cave Network
The longest cave in Asia, Shuanghedong is a monster located in Central China in the Guizhou Province. Stretching more than 150 miles, it’s an underground wonderland of rivers, multiple levels, and waterfalls. The cave network was discovered in 1987, and it is still an enigma to scientists.
Much of the cave remains unexplored, with approximately 20 official expeditions completed. Recent laser mapping has shown that the cave is larger than initially expected, and it’s swiftly moving up the list of longest caves in the world. There are eight main caves and approximately 200 branching caverns. The caves are tourist friendly and can be easily entered after a safety briefing at Shuanghedong National Geopark.
9. Sac Actun Cave System
The Yucatan Peninsula of Mexico is well-known for its geological anomalies, including hidden beaches, sinkhole cenotes, and water-filled caves. The big daddy of them all is Sac Actun, one of the longest underwater caves in the world. Located in the Mexican state of Quintana Roo, it spans over 200 miles of submerged caverns and interconnecting chambers, branching off the popular Gran Cenote in Tulum.
It was recently discovered that Sac Actun is connected to the adjacent underwater cave complex of Sistema Dos Ojos. This new connection gave Sac Actun the chops it needed to overcome its neighbor, Sistema Ox Bel Ha, as the largest complex in Mexico. The cave system has multiple entry points from open-air cenotes dotting the area. Many are filled with swimming tourists who have no idea what kind of labyrinth lies beneath them. Most assume they are swimming in a solitary cenote, not realizing that they are all interconnected in a giant maze of waterborne amusement parks. Many of the caverns are accessible by snorkeling. Others require scuba gear. It’s highly advised to hire a local scuba guide who knows the routes through the cave system.
10. Jewel Cave
For our last entry on the list, we head back to South Dakota. Surrounded by Black Hills National Forest, the views above ground are almost as gorgeous as those below. The cave gets its name from the variety of colorful crystals embedded in its walls. The cave spans over 200 miles, making it one of the largest caves in the world and one of the most stunning. Despite feeling remote and uncharted, the cave is actually quite well-mapped.
Cavers and tourists can choose from several expedition options of varying levels. Quick visits can be done by the 20-minute Discovery Tour. Most visitors will choose the hour-long Scenic Tour, and avid cavers can hop on the four-hour Wild Caving Tour. They even offer a lantern-guided historic tour with a period-dressed ranger.
There are a couple of caves that didn’t make the list but bear mentioning. One is not tourable but is outstanding. The other is not that big but offers the ultimate tourist adventure!
Cave of Crystals
Under the tiny mining town of Naica, Mexico, lies an underground labyrinth plucked from the reels of a sci-fi thriller. In 2000, some miners stumbled upon the entrance to the cave and made the find of a lifetime. They discovered a world of truly massive crystal structures within a limestone cave below a known crystal cave. Soaring to over 35 feet and weighing as much as 12 tons, these mammoth selenite crystals jut up from the cave floor in a mesmerizing, interwoven fortress of sparkle. There’s just one problem… or two.
Due to the water table of the Chihuahua Region, the cave is often flooded. When it isn’t, the same boiling magma that created the overgrown jewels keeps the cave temperature around 130 degrees Fahrenheit with at least 90% percent humidity. Without special equipment, the average human can’t stand the conditions for more than ten minutes. The cave has been featured on Angry Planet, Life After People on the History Channel, and the Discovery Channel’s Naica: Beyond The Crystal Cave, and streaming these on YouTube is as close as you’re going to get to climbing on these bedazzled behemoths.
K’an Ba Caves
Located just across the river from Semuc Champey National Park in the deep jungles of Guatemala lies one of the most outstanding caving adventures available for novice cavers. First of all, Semuc Champey is an excursion to reach and one of the most beautiful sets of natural limestone pools on Earth. You take a bus to the nearest city of Coban, hop a collectivo (locals van) to the mountains, get transferred into the back of a local’s truck equipped with roll bars, and set off on a winding mountain road to the park.
Don’t worry. The local children will greet you with homemade chocolate to soothe your nerves once you arrive. From there, you cross the big yellow bridge to private property and book a guided tour by candlelight to the caves. Your tour is done by a local Mayan guide who will educate you on the medical plants of the jungle… and possibly paint your face with them. You’ll then get a simple white wax candle and enter the dark labyrinth.
The cave is a series of water-filled chambers, many of which are very deep, that you will navigate by rope bridges and candlelight. You’ll rappel up waterfalls, go down a natural waterslide, stand in the pitch black and listen to the calls of the bats in the inner caves, and finish off the adventure with a three-story jump off an internal cliff into the black abyss below. There are no safety waivers, no helmets, no life vests… just pure, unadulterated adrenaline. You’ll finish off your tour with a rope swing into the river!
Now that we’ve piqued your interest and your adrenaline meter is pumping, it’s time to plan your trip to explore one of the largest caves in the world. Pick one, or start ticking them all off the list one by one. While some of these are difficult to get to, others are a breeze and offer jaw-dropping surroundings that will put your skills to the test and blow your mind with beauty!
Not feeling the whole cave vibe right now? That’s cool. Check out our guide on “How to Hike the World’s Active Volcanoes” instead.
For more adrenaline-pumping adventures, take a look at “Where to Find the Best Whitewater Rafting in the U.S.”
Frequently Asked Questions
The longest cave in the world is Mammoth Cave in the state of Kentucky in the United States. It reaches a length of 400 explored miles. Mammoth Cave National Park is also a UNESCO World Heritage Site!
The world’s four deepest caves are in the Ural Mountain region of Abkhazia, Georgia. The deepest is Verëvkina Cave. It’s 2,212 meters deep! Be careful exploring this one.