Twenty-five years ago, in a remote section of central Vietnam, a young man named Ho Khanh was out for a walk. He knew this sparsely populated region, a 30-mile stretch of dense jungle between the South China Sea and the border with Laos, better than most.

In fact, he often spent weeks on end trekking his way through the overgrown hills in search of timber and food to make a living. On one of these hikes, he stumbled across an opening in a limestone cliff and saw white clouds billowing out from underground. He could also hear the distant rush of an underground river, but he had no way to investigate, as the crevice he had found in the rock was deep and seemingly impossible to enter. He went on his way, and soon forgot the cave’s location entirely.

Hang Son Doong

That same year, in the same remote section of central Vietnam, two researchers with the British Cave Research Association were on the hunt for massive caves. The limestone bedrock in this area, with its relatively soft composition and susceptibility to water erosion, created an enormous karst region—a landscape of caves, grottoes, and tunnels running beneath the forested hills. When Howard and Deb Limbert, the researchers, spoke with Ho Khanh, they found his account tremendously compelling. An underground river? Clouds formed beneath the earth? This sounded like the kind of thing that cave researchers dream about, and they urged him to remember anything he could about the cave’s location.

Unfortunately, numerous expeditions into the tangled underbrush proved futile, and it seemed like Khanh’s cave would be lost to the jungle once more.

Hang Son Doong

Then, in 2008, Khanh found it again.

And that’s a good thing, because it is, in a hyphenated word, jaw-dropping. The cave system, which is called Hang Son Doong (literally “Mountain River Cave” in Vietnamese), stretches more than five and a half miles – from the crevice that Ho Khanh discovered in 1991, beneath an overgrown mountainside, through one enormous cavern and a multitude of lesser chambers, and over a 200-foot wall of mud and calcite that was once thought to be impossible to climb.

Hang Son Doong


Son Doong is somewhere between two and five million years old and was formed as a river flowing across the soft limestone slowly burrowed into a fault, carving out the massive underground tunnel. Today, that river (the Rao Thuong) runs along the bottom of the cave, dwindling to a series of still ponds in the dry months before rising (sometimes by as much as 300 feet) to a thundering torrent that makes the cave impassable during most of the flood season. After lying hidden for millennia, this massive cave system has only been fully explored in the past few years, and official guided tours began in 2013.

Even getting to the mouth of Son Doong is a difficult feat. From Dong Hoi, the nearest major city, it’s a 31-mile journey to the “base camp” town of Phong Nha, followed by a two-day hike into the jungle to reach the mouth of the cave. This “pre hike” is a journey in itself, as you’ll climb hills, cross rivers, explore minor caves, and visit Ban Doong, the only village in the National Park, to learn about the culture and tradition of the ethnic people who make their homes here.

Hang Son Doong

AN UNDERGROUND WORLDScreen Shot 2016-02-02 at 12.14.20 PM

And after this mini-adventure, the real fun begins. While wearing a safety harness, you’ll climb down more than
200 feet from the entrance to the cave’s floor, a spot from which you can truly appreciate how massive Son Doong really is. From there you walk, scramble, and boulder your way through the first few chambers of the cave, crossing the Rao Thuong River several times. All this effort is rewarded with one of the most breathtaking views in the entire cave system – the Hand of Dog.

Perhaps the tallest stalagmite in the world, at over 230 feet, the Hand of Dog towers over the cave’s floor, silhouetted perfectly by the cave’s first doline behind it. The name arises from the stalagmite’s shape, which resembles a dog’s paw in profile.

From the entrance until reaching this skylight, darkness rules the cave, kept at bay by the powerful light sources provided by the tour operator. This makes for stark differences between light and shadow and gives the cave an otherworldly, almost moon-like quality. But most of Son Doong’s most stunning scenery comes courtesy of Mother Nature.



As the cave has only been open to visitors since 2013 and sits in the middle of a protected national park, you won’t find any Four Seasons around the corner. Even so, a trip this unique deserves a lodging just as special, and three of the best accommodations are ideally located near the jumping off point for any tour of Son Doong.

The first, Oxalis Home, is a full service hotel located onsite at the Oxalis Adventure Tours headquarters. Perched on the Son River, the Oxalis Home enjoys some of the best views in the region and allows guests access to their private beach and the use of their kayaks. The hotel’s amenities include complimentary bicycles, breakfast, and laundry service (which will come in handy after slogging through the cave’s mud flats).Balcony (River view room)

A bit further out of town, overlooking rice paddies and the limestone hills, lies Phong Nha Farmstay. Contrary to its name, the Farmstay is actually a sprawling, ranch-style hotel, offering all kinds of amenities. The swimming pool is refreshing on a hot summer day, and the evenings are filled with either live music or outdoor movies on the hotel’s big screen projector. An interesting quirk— the second-floor patio doesn’t have a bar—drinks are served via crate and pulley system from downstairs. Breakfast is included at the Farmstay as well.

For those looking for a little more relaxation before and after their big adventure, there’s Phong Nha Lakehouse Resort. Overlooking a gorgeous lake (hence the name), the Lakehouse stands removed from town and offers high-quality lodging in a more tranquil environment. The food is top notch, and caters to both Westerners and Vietnamese. The resort has a pool, in addition to the lake.



Though located hundreds of miles from either of Vietnam’s major cities (Hanoi and Ho Chi Minh City), Dong Hoi is home to a robust culinary scene. It’s a 45-minute drive from the Oxalis lodging, but the food and shopping are worth the trip. The city of roughly 160,000 caters to every palate and offers a range of restaurant options, from traditional, sit-down places to off-thebeaten- path cafes where you’re made to feel like a local.

Our pick of the bunch is 7th Heaven, a casual spot in the heart of Dong Hoi serving both Western and Asian fare. The menu doesn’t feature any gourmet dishes, just hearty, stick-to-your-ribs meals that run the gamut from a Vietnamese banh mi sandwich to a quarter chicken with honey and steamed vegetables. And after four or five days in the unforgiving jungle, we’re betting something simple, homemade, and filling is just what the doctor ordered. And speaking of docs, 7th Heaven is run by one—an American who goes by Doc, that is. He and his wife Ann own the place, giving travelers of all nationalities a taste of good old American home cooking in a land far, far away from the U.S. of A.

fresh spring roll with peanut sauceThe small town of Phong Nha, where you’ll be staying before and after your trek, feels a bit like an Old West town, if the Old West were set along a jungle river. Though mostly confined to either side of the main street along the Son River, the town offers a host of dining options for those travelers wishing to stay local. Not to be missed is Phong Nha Bamboo Cafe, a neighborhood restaurant long on flavor and friendliness, and short on price. Run by a group of friends with barely any hospitality experience, the Bamboo Cafe has become a favorite among locals and travelers alike. Whether you come for the low-key, welcoming atmosphere, the large outdoor patio and cocktails, or the multitude of hearty dishes with intriguing names (Wonder Balls, anyone?), you’ll probably end up staying longer than you planned—and that’s a good thing.12228046_914994961881554_84711733_o-2