A Farmer Accidentally Stumbled Upon The World’s Biggest Cave

Ho hadn’t been on the lookout for anything special in the forests: he was just keeping an eye out for food and a specific type of wood that could earn him some extra money. The timber in question was agarwood, which can be used to create medicines, perfumes, incense, and a whole host of different items. It’s extremely valuable, so the farmer was hoping to get lucky. Instead, his search was cut frustratingly short by the storm.

With nothing else on his mind except escaping the rain, Ho sought whatever kind of cover he could find. Eventually, he reached the side of a limestone cliff, only to spot something quite extraordinary. There was a huge hole near the base of the rock, which he carefully approached. Might this be the perfect place to ride out the storm? Before Ho had decided one way or the other, he made another surprising observation: oddly, there was mist pouring out of the opening.

And that wasn’t all. In addition to the vapor, Ho picked up on a very distinct noise coming from the opening. Yep, it sounded like there was a raging river further inside, suggesting that this hole was actually a pretty deep cave. On top of that, powerful gusts of wind shot out of it into the forest as well, which prompted Ho to leave the area. He didn’t want to take a chance and venture any further into the cavern. 

So, Ho headed back home, paying little mind to what he’d seen in the forest. It was a sight he wouldn’t soon forget, but why worry about it? Not long after that, the farmer started up a conversation with a couple named Deb and Howard Limbert. By chance, the pair were in Phong Nha as part of their work with the British Vietnam Caving Expedition Team, researching the nearby caverns. Unsurprisingly, Ho recounted what he’d previously found.

Within moments, the Limberts were desperate to know more. You see, prior to that chat, the pair had believed that a significantly big cave was close by after consulting their research of the terrain. And once Ho casually noted that he’d seen clouds and heard a river inside the limestone cavern, they felt he might’ve found it. It’s the kind of coincidence you’d only normally spot in a movie! There was one problem, though, and it was a biggie.

While Ho was more than willing to help his new friends, he had absolutely no idea where the cave was. The farmer hadn’t taken note of its exact location ahead of his trip out of the storm-drenched forest. But the trio refused to throw in the towel. Determinedly, the trio set off into the woods again, in the hope that Ho might be able to retrace his steps. 

It didn’t work, though: they failed to locate the cave, and that appeared to be that. Yet Ho wasn’t completely deterred by the setback. Whenever he ventured into the forest, he kept a watchful eye on his surroundings, desperate to stumble upon the opening once again. Now, you’d think it’d only be a matter of time until he got lucky, but our hero ended up doing this for years. It really was like searching for a needle in a giant haystack.

So let’s jump forward to 2008 now. By this point, it’d been 18 years since Ho had first made his discovery inside Phong Nha-Ke National Park. And just as on that stormy day in 1990, the farmer was in the forest once more searching for food. As he navigated the terrain and kept his eyes open for any produce, something familiar came into focus. It couldn’t be… could it? Remarkably, by chance Ho had finally managed to relocate the cave.

Stunned that he’d finally uncovered the mystery cavern for a second time nearly two decades on, Ho then made a clear note of the location. He wasn’t going to forget the route on this occasion! After he got back, the Phong Nha resident attempted to reach out to the Limberts, who were no longer in the area. Thankfully, he did manage to reach their team.

So in April 2009 Howard and his group joined up with Hanoi University of Science’s Geography Department to take a closer look at the cave. And yes, Ho joined the party, too. There was no way he was going to miss out on this! But who would earn the distinction as the first person to enter the massive cavern? Well, Peter MacNab, who formed part of the British Vietnam Cave Expedition Team’s party, stepped up.

The excitement must’ve grown with each passing step when the team first ventured into the limestone fissure, ready to survey their mysterious new surroundings. But none of them could’ve predicted what they’d eventually uncover. By the end of that week, Limbert and his team had some game-changing findings to share with the world, as well as a name for the cave. And though the group had no idea at the time, still more revelations would soon follow.

After journeying deep into the bowels of the cave during their first expedition, the team were stopped in their tracks by a giant piece of flowstone rock. There definitely appeared to be more to explore beyond it, as light was breaking through near the top. They didn’t have the tools to get around the obstacle, though, so the explorers packed their gear and returned to the entrance. Yet despite the stoppage, Limbert was convinced that they’d just uncovered the biggest natural limestone cave on the planet.

At the same time, Ho and the team had also been throwing around some potential names for the cave. Given the attention that was no doubt coming its way, it was certainly going to need one. In the end, they landed on Son Doong. So what happened next, then? After all, the survey hadn’t been fully completed yet thanks to the flowstone. How much more was there to see?

Well, nearly 12 months later, Limbert and company came back to Son Doong in March 2010. And this time, they had the tools to scale the huge slab of flowstone. Due to its size, this obstacle has since been dubbed the “Great Wall of Vietnam”: a fitting moniker! Thankfully, the group managed to reach the summit before continuing their survey. As it turned out, there was only another 400 meters between that point and the cave’s exit, bringing this extended journey of exploration to a close.

As a result, the cave’s figures could now be finally confirmed: the stats made for eye-opening reading! Incredibly, Son Doong measures around five miles in length. To help you visualize that, you could fit roughly 100 New York City blocks in that space. Its overall volume measures a whopping 38.5 million cubic meters. And the cavern also reaches skyscraper-dwarfing heights: over 650 feet in places.

No other natural cave on our planet can touch those numbers, as first confirmed by National Geographic TV. It was further rubber-stamped three years later when the Guinness Book of World Records included Son Doong in its 2013 volume as the world’s biggest cave. Mind you, as we hinted a little earlier, more surprises were in store going forward, which brings us to the spring of 2019.

During that period, Limbert got in touch with three divers from the United Kingdom named Chris Jewell, Rick Stanton, and Jason Mallinson. He extended an invitation to them to explore the water systems inside Son Doong, in a bid to learn more about the cave. By doing so, the guys would become the first people to ever attempt this. They accepted the task, but none of them could’ve foreseen what they’d eventually uncover. 

The group got to work in April 2019. As the dive progressed inside Son Doong, the trio stumbled across an underwater passage that no one had noticed before. Curious, they then started to head towards the bottom, only to realize that it went much deeper than they originally thought. The limitations of their equipment meant initially the divers couldn’t go any further down than 255 feet. That didn’t spell the end of their exciting exploration, though.

You see, with the aid of a lead weight, the three divers were able to get a better idea of just how deep the passage was. In the end, they surmised that the depth was pretty close to 400 feet. In addition to that, the trio also speculated that the waterway covered a distance of just under a mile. Speaking to CNN in May 2019, Limbert revealed, “Now that we know how deep it is, we’ll bring the special gases [oxygen-helium mixture] with us next time to enable long, deep dives.”

Here’s where it got really exciting, though. Prior to the dive, Limbert and company had been aware that the water inside Son Doong connected to a separate cave in the area, the massive Hang Thung; they just didn’t know how or where. But now, thanks to the efforts of the divers, the group had their answer. Keeping that information in mind, when joined with Hang Thung, Son Doong proved to be much larger than the 2010 survey had suggested. We’re talking an extra 1.6 million cubic meters!

Touching on that, Limbert told CNN, “It would be like someone found a lump on top of Mount Everest, making it another [3,000-plus feet] higher. Any cave in the world will be able to fit comfortably inside Son Doong when it’s connected: it’s just outrageous in size. I think it’s incredible that something as important as the world’s largest cave is still being explored and better understood. This latest discovery shows there are still an awful lot of things to uncover on this planet.”

“It’s really exciting,” Limbert added. And it’s hard to disagree. Yet for as cool as this all is, we don’t blame you if you’re struggling to picture what Son Doong has to offer beyond its entrance. Aside from the size, what is there to get excited about? Well, we’ve got you covered on that front. Yep, it’s time for us to take a tour of our own inside the cave from the comfort of our chairs. 

After passing through the rather ominous-looking entrance, there’s a very steep, rocky hill leading into the cave, which is bathed in darkness. It’s more than a little creepy! But once lit up, you get an immediate sense of just how spectacular and vast the interior really is. Stalactites and stalagmites adorn the route leading down to the river which Ho had heard all those years before. If the sound of running water relaxes you, you’d be in your element here.

By crossing the river, you’ll then enter one of Son Doong’s most notable caverns. Not only does it house an enormous stalagmite, but the space is so vast that a Boeing 747 jet could pass through it. We’re serious! Going back to the aforementioned stalagmite, it measures close to 230 feet in size. It’s got a name, too, although we’ll be surprised if you can guess it. The stunning chunk of rock was dubbed the Hand of Dog upon its discovery back in 2009.

If you thought that was something, though, wait until we head into the next astonishing section of Son Doong. Yes, after leaving the Hand of Dog behind, the following area is bathed in natural light thanks to a giant opening in the rocks above. As a result of that, plants and vegetation have been able to thrive here for the last 500,000 years. The cave itself is said to be up to 5 million years old.

But while that space is definitely impressive, the humorously named Garden of Edam further ahead might just beat it. With a hole in the ceiling that spans more than 530 feet, a rainforest has managed to grow across this entire area. Dinosaurs wouldn’t look out of place rummaging through the vegetation here! It’d be easy to forget that you’re still in a cave as you navigate all the eye-catching greenery. Oh, and don’t think you’re alone. Certain animals have made this place home.

Limbert shed a bit more light on that while chatting with the Lonely Planet website in June 2019. He explained, “We’ve seen monkeys that are able to climb down to visit the jungle within the cave where they collect snails. We’ve also seen snakes and other animals, including squirrels, rats, flying foxes as well as birds and bats.” It’s a fully-fledged ecosystem: imagine how surprised his team must have been when they found this back in 2009.

The stunning sights don’t end there, though, as hard as it might be to believe. Once you leave the Garden of Edam and walk down a slope heading back into the darkness, you’ll enter a fairly plain-looking cavern. Other than the rock formations, there doesn’t seem to be much to catch the eye. But upon closer inspection, you may just spot some species of wildlife that you’ve never seen before. And their appearance is a direct result of their murky surroundings.

Yes, during the initial expeditions, Limbert and company found a number of new spider, shrimp, plankton, scorpion, and fish species in the darker parts of Son Doong. Their skin is a ghostly white and none of them have eyes. They’ve each adapted to their dark home, making them unique. Few people have ever seen these animals in the flesh, so that’s another perk of visiting this incredible cave in Vietnam. It’s the gift that keeps giving!

Moving on from that cavern, there’s another watercourse that leads you deeper into the cave, until it reaches the Great Wall of Vietnam. And that’s where our tour concludes. Yet if you really want to experience Son Doong in the flesh, and see all this amazing stuff first-hand, it’s an achievable dream. You’ve got to be prepared to pay for the privilege, though, as well as ensuring your fitness levels are tip-top ahead of time.

Since 2013 — roughly four years after the first expedition — people have started to be allowed to tour the caverns for themselves. Due to the conditions, exploration is only allowed from January until the conclusion of August, while no more than ten tourists can make up a single party. The spots are priced at around $3,000 each, with the tours spanning four days. Nope, this isn’t a quick in-and-out of the place! You won’t be traveling alone, either, in case you were curious.

All of the tour guides who lead the groups are people that were part of that first expedition in 2009. Alongside them, parties are also made up of chefs, a safety assistant, a park ranger, and porters. It’s quite the troupe, but given how epic the tours are it certainly makes sense. As for the distance that gets covered, you won’t just be traversing the five miles inside Son Doong over those four days.

Yes, you’ve got to get to the cave first! That means navigating your way through over 15 miles of forested terrain. So like we mentioned earlier, fitness will be key here. You don’t want to be exhausted before getting into the meat of the tour. Oh, and lest we forget, walking isn’t the only thing you’ll be doing once you arrive at Son Doong. You’ll have the chance to scale the Great Wall of Vietnam as well, mirroring the efforts of Limbert’s team.

Each night, you’ll set up camp with your fellow travelers and sleep in cozy tents. That’s especially cool once you’re inside the cave, as you can take in the surroundings while chilling out in a sleeping bag. It’s fair to say that most other campsites pale in comparison! During these quiet spells, you’ll probably need a change of clothes handy, too. After all, as Limbert himself has noted in the past, your outfits will get caked in mud as the journey progresses.

Reflecting on the tours, Limbert continued his conversation with CNN in May 2019. He said, “People love it because they’ve never done anything like it before. Obviously, you have amazing stalactites and the world’s largest stalagmites. They are so spectacular. [It’s] definitely not just a stroll. There are lots of river crossings, superb jungles, mountains and cliffs all around, plus lots of wildlife like birds and monkeys. A lot of people find the scenery as spectacular as the cave itself.”

Wondering what’s the biggest highlight of the Son Doong tour? After giving it a bit of thought, Limbert’s answer was fascinating. “There’s a passage that has beautiful, 400-million-year-old fossils,” the explorer explained. “We take travelers to see these fossils and, once you’re down there in the dark, there’s a place where you can go swimming. Everyone loves… swimming in the dark in the cave. It’s a really unusual experience.”

In total, no more than 1,000 people get to experience this incredible tour every year: you’ll be in a very select group if you’re fortunate enough to do it. Limbert summed that up quite nicely, adding, “At this point, more people have climbed Mount Everest than have gone into Son Doong. And even those who have summited Everest say that exploring Son Doong is outrageous, that it’s the best place they’ve ever been in their life.”

Since becoming a tourist attraction, Son Doong has also completely transformed the local area. Thanks to the steady stream of visitors paying big money, the economy has come on leaps and bounds, allowing Phong Nha residents to improve their living situations. Plus, with more caves being found as time goes on, that’s sure to improve things even further. Son Doong itself hasn’t been completely explored, either, so future discoveries are sure to keep the spotlight on this little thriving community.

And if you were curious what happened to Ho after he followed the expedition team in 2009 you’ll be pleased to know that the farmer has also been able to enjoy the benefits of Son Doong’s discovery. He’s been known to join the tours from time to time, while also setting up porters prior to their trips. On top of that, Ho fronts the “safety response group” as well. So thank goodness for that storm back in 1990: who knows if any of this would ever have been made possible without it.