EXPEDITION TO THE WORLD’S LARGEST CAVE
The wonders of Vietnam’s Hang Son Đoòng weren’t even known to the world 10 years ago
The warning flag went up when I came across the mandatory requirement for medevac insurance.
I had applied for a spot on an expedition to Hang Son Đoòng; the world’s largest cave. Located deep inside Phong Nha-Ke Bàng National Park in North Central Vietnam, Son Đoòng was first discovered in 1991 by a local man while seeking shelter from a storm.
So hidden was the entrance, he could not remember its exact location until rediscovering it again nearly two decades later in 2008.
It was shortly thereafter that the first cave explorers from the British Cave Research Association entered and discovered its immensity. Now it was my turn.
After flying into Dong Hoi, I made my way to the village of Phong Nha where my guides and expedition team were based.
An orientation that night set the stage for what the next five days and 50 km of trekking would look like.
Talk of leeches and snakes in the trees caused beads of trepidation on my forehead.
After a restless sleep wrought with jet lag, dread and anticipation, it was time to load up and make the 45-minute trip up a winding, narrow road to the trailhead.
Our porters, young lads in their 20s, pulled on mammoth packs that would sustain us all for four nights underground. Within moments, they disappeared into the jungle with the stealth and agility of mountain goats.
I grabbed my pack, loaded with a ridiculous amount of camera gear, then started into the thick and humid jungle. After a few miles, we passed through a tiny settlement of about 30 people, then meandered along and through the Rao Thuong River shouldered by a valley of Karst mountains and thick jungle. We made more than a hundred water crossings on this journey and trench foot was a serious possibility. I was glad I had self-draining boots.
As the light of day began to wane, we arrived at the entrance to Hang Én, the world’s third-largest cave.
It is necessary to pass completely through this cave to reach Hang Son Đoòng, so we strapped on our helmets and headlamps, and stepped into the darkness.
A scramble up an enormous pile of sharp-edged boulders led to an overlook which was our first camp. Our speedy porter team had fully assembled a temporary community of tents along a sandy stretch inside the mouth of the cave, next to the river, while cooks prepped the evening meal. Dinner that night was a buffet of fried pork, complemented by an assortment of vegetables, including bok choy, beans and broccoli, as well as fruit such as wee oranges and juicy dragonfruit.
Our lead guide and caving expert appeared an unlikely sort for such a strenuous physical activity such as this. Ian Watson, a.k.a. Watto, is a 60s-ish semi-rotund caver, who was one of the first to explore Son Đoòng in 2009. Watto’s jovial demeanour was infectious as he recounted stories of past trips with our other lead, Adam Spillane.
The next morning began early as the mouth of the cave filled with the dawn of a new day.
A hearty breakfast fuelled the group as we headed further in.
Hang Én bores 1.6 km through a mountain with a cross section that reaches about 170 metres in width.
It was only when we turned on a few 32,000-lumen lamps to illuminate the upper reaches of the cave that the size became apparent.
Our team was reduced to mere dots of light under a 30-storey ceiling of rock.
The scrambling continued as we climbed up, over and through rocks before finally emerging on the other side of the mountain.
We followed the river for another few kilometres before climbing up the steep, muddy slopes of another mountain. Halfway up, we found the jagged smirk of Hang Son Đoòng’s mouth. I could feel the wind of its breath and hear a faint rush of water in the back of its throat as I hooked onto a fixed rope and began to rappel into the depths.
The entrance to Son Đoòng is significantly smaller than that of Hang Én, so you are enveloped in darkness almost immediately.
Son Đoòng is more than five kilometres in length and at one point its ceiling rises an unfathomable 200 metres; more than twice the height of the Statue of Liberty.
As our team explored deeper into the cave, we reached a doline; an area where the cave ceiling collapsed millenniums ago, exposing the darkness to a world above.
Over time, light, rain, soil and seed entered the cave and a micro-jungle emerged. The humidity mixing with the colder temperature of the river combined to produce clouds, creating a scene straight from the dawn of time.
We climbed through the doline on our way to our second camp, where we took a much-needed rest.
The next day, we continued deeper into the cave, past skyscrapersized stalagmites and enormous icicles of rock stalactites, before approaching a second doline and its lush jungle coined The Garden of Edam.
Our next camp awaited us on the other side. A brief stop for a bite and then we continued to the formidable end of the cave; a small lake bounded by the 15-storey Great Wall of Vietnam; a perpetually wet fortress of sculpted rock that looks straight out of a film set for Alien.
In the next few days, we retraced our way through both caves and then through the jungle back to civilization. My exhaustion was overshadowed by the prehistoric beauty I had experienced and the relief that we didn’t need to call for a medevac.