The Curious Discovery of Son Doong
To enter the magnificent cave called Son Doong, spending any appreciable time within its boundless caverns and self-contained, self-supporting aquatic eco-systems, is to experience something so dramatic and beyond-the-realm of the imaginable. Many find it difficult to comprehend how this natural wonderland of epic measure remained a complete mystery to not only the modern world but quite possibly every single soul throughout the whole of human history. Well, since 1990, anyway.
Find that hard to believe do you?! We did too. Add us to the “no way in hell” camp (well, at least at first read.)
A little backstory for you, it seems that a local farmer and gatherer, Ho Khanh, was trekking through lands near the limestone cliffs, now known to mark Son Doong’s most notable entrance. He noticed what appeared to be a small hole in the cliffs and from it, noticed a few clouds of what appeared to be smoke, rising. He approached slowly but found no sign of smoke. As he neared the entrance, he heard what could only be described as the sound made by a swiftly moving river. The only catch? This was his home. He had trekked in and around these lands his entire life. He knew of no such river – well not in and around that area, anyway.
Of course, he pressed on. GAH! Wouldn’t you turn right back around?! Anywho, after days of exploration he returned home – reportedly so disoriented, amazed and bewildered, he could barely piece together where the entryway had been. As fate would have it, the moment would come with a fair share of serendipity. Son Doong was destined to be revealed to the world.
Upon his timely return to town, Ho Khanh ran into some visiting, get this, cave explorers. He told them of his recent discovery and as you might imagine … they had to experience it for themselves. The story was almost too outlandish to believe – a cave with a river and billowing clouds. It might have been ridiculous enough to disregard to most. However, these are cave explorers we are talking about.
The thing is, Ho Khanh was too confused to remember where he had entered – a memory completely lost to the otherworldly experience. There was no direction to point – until 2008. Almost twenty years later, another trek brought him to the same exact point. His heart raced. This time, he did not enter. He raced back home and contacted old confidants Howard and Deb Limbert. He led them and their curious team to the “Mountain River Cave.”
How Big Is It?
Frightfully big. Son Doong is more than 5km long with some areas climbing to 656 feet in height and 492 feet in width. Cavernous is an understatement. To give some perspective, one could easily fit a square city block harvested from the heart of Chicago, with more than a few 40 story skyscrapers. There are megalithic stalagmites stretching upward from the cave’s floor, some extending as much as 230 vertical feet.
In short. It is incomprehensibly big.
What’s Inside?
Well aside from the clouds, rivers and stalagmites large enough to own their own zipcodes – a better question might be, “What ISN’T inside?” Imagine yourself standing in a cavern that would easily accommodate a no-nerves jumbo jet fly through – one with enormous stalagmites like fangs threatening from above – many lost in the fog of misty clouds, resultant of the cave’s self-contained, localized weather system.
There are fossils, strewn literally everywhere, evidence of a lost, long-forgotten world. Cool wind summoned by the subterranean Rao Thuong River, its formations most critical contributor.
So, Are There Bats?
Beyond a copious amount of flora, you should also expect to find some fauna who were keen enough to settle into this long-lost geological garden paradise, kiloyears prior to mankind’s’ first footstep.
Oh, and to answer the question … Yes. It’s a cave. Of course, there are bats. In fact, several species call Son Doong home. But the fun doesn’t stop there.
Current numbers suggest there are 500+ vertebrate species that have been identified in the parklands surrounding the cave, as well as hundreds of more invertebrates. It is thought that most (whether “scurriers,” “crawlers” or “flappers”) have woven their way in some form or fashion into the cave’s unique and diverse ecosystem.
Although they have not yet been “officially documented” as this cave’s residents, many certainly do make their homes in the cave’s open areas. For example, Phong Nha-Ke Bang (the surrounding park) is known for having the world’s largest population of langur monkey.
There are also scores of rare birds, including the Chestnut-necklaced partridge and the short-tailed scimitar babbler. And get this, there are more than 250 butterfly species certain to drift through the cave’s exposed passages. In recent years, we have been alerted of a few new species discoveries including little-known gecko “scientiadventura,” Orlov’s treefrog and the striped hare.
Cool, huh?

Can you See It?
The cave has only been open to the public since 2013. In fact, there have been fewer eyes laid upon it than Everest’s Summit, and that is saying something.
While travel costs can fluctuate, a multi-day, fully guided tour including food costs in and around 3K USD. Keep in mind, every penny will be worth it. You’ll never again see anything quite so inexplicable, intoxicatingly beautiful, intimidating and otherworldly, no matter where you stop as your lifetime of journey unwinds before you. (The only thing comparable might have been The Land of the Lost, had it not been entirely made up.)