A version of this article was first published in the Straits Times Newspaper of Singapore on July 7, 2019.
The siren call was simply impossible to resist. The moment I first heard about its existence, I simply knew that I had to find a way to see it with my own eyes. Indeed, Son Doong Cave, or Hang Son Doong as it is also known, is the largest cave in the world. It is an otherworldly place full of wilderness and grandeur, a true masterpiece of nature with awe-inspiring landscapes, and enormous stalagmites and statuesque stalactites, hanging from the ceiling and rising from the ground like alien species. They say life is about great friendships and spectacular adventures. Our week-long jungle expedition to the heart of Son Doong cave in Vietnam turned out to be precisely that, an unforgettable journey to a magical place as ancient as time, where we found ourselves constantly at a loss for words in front of so much stunning beauty and splendour, as we solidified friendships.
Located in the heart of the Unesco-listed Phong Nha-Ke Bang National Park in the Quang Binh province of Central Vietnam, it was initially discovered by a local lumberjack named Ho Khanh in 1991. He did not dare venture in because he thought the powerful and mysterious wind blowing from inside the cave came from monsters of local mythology. The cave was then explored in 2009-2010 by the British Cave Research Association. It is now open to the public, but only officially since 2013.
In Vietnamese, Hang Son Doong means “Mountain River Cave,” and the grotto wears its name well, since it has its own underground jungle and ecosystem, with trees rising up 30m above ground, and a sinuous river that rushes through its gigantic chambers — distinct features that set the cave apart from many other grottos around the world.
The journey to the entrance of Son Doong cave involved two days of intense trekking through the thick jungle, multiple river crossings, and one night of camping in Hang En Cave (the third largest cave in the world). Once at the entrance of Song Doong, we harnessed up and abseiled down about 80m through tight and slippery passages, scrambling over huge boulders into the cavernous belly of the mother of all grottos.
Travelling through the cave’s depths required intense concentration. We had to stay alert at all times, lest we trip on the slippery rocks, and tumble down into a ravine lined with razor-sharp stones. Up and down we went using the wooden ladders wedged between the rocks; sometimes removing our backpacks so that we could squeeze through tiny crevices, splashing across icy rivers, wading through muddy streams, pulling ourselves up with ropes or sliding down on our muddy bums over sloping stone walls, and balancing precariously on narrow and rickety bridges to cross wide-open echoing spaces.
The cave’s proportions are extraordinary. Its main chamber is the largest in the world by volume (38.5 million cubic metres), measuring more than 5 kilometres in length and running approximately nine kilometres in total. Its largest section peaks out at 200m high and 150m wide. The only way to get a real sense of perspective on the sheer size of Son Doong is to have fellow trekkers scatter throughout the limestone galleries. Even then, it’s hard to properly comprehend the enormity of a place that could house an entire New York City block or could even store 68 Boing 777 aircrafts in its main passage.
The difference in temperature between the air inside and outside of the cave creates hovering clouds of mist that give rise to a mysterious and surreal atmosphere, enveloping many areas of the cave in a dense fog and contributing to the eerie sensation. The vegetation is extremely diverse, with lush and green foliage in parts where sun rays break through the openings, and practically non-existent in the hallowed and dark chambers of the cave.
Because of its colossal size and the high levels of rainfall in the region, erosion happens at an accelerated rate. Occasionally, the weight of the limestone gives way and collapses, creating what is known as a “doline.” Derived from the Slovenian word “dolina,” meaning “valley.” These sinkholes form huge gateways to the outside world, and at certain times of the year when the conditions are right, incredible sunbeams penetrate through these exposed sections, creating a mesmerizing light show.
On occasion, during pauses in our itinerary, we would look up and shine our helmet’s torchlights on the colossal limestone ceiling above our heads and marvel at the awe-inspiring majesty and beauty of this underground cavern. In those moments, we would be reminded of how unbelievable and rare this whole experience truly was. In reality, fewer people have seen the inside of Son Doong cave than have stood on the summit of Mount Everest.
Our Vietnamese guide, Vu, shared that the cave was estimated to be about two to five million years old and was initially formed by river water eroding away the weak limestone underneath the mountain, creating huge skylights. In many parts of the cave, we saw fossils believed to be millions of years old and thousands of cave pearls neatly packed into terraced compartments on the grotto’s floor. The cave pearls are a natural phenomenon formed over hundreds of years when dripping water creates layers of calcite that build up around grains of sand.
At times, we would encounter crawling white insects, almost transparent in hue, that had probably never seen the light of day. Other times, we would step over the remains of small animals such as deer or rats, their bones mixed with mud and dust. One morning on the first day of the expedition, we were awakened by the chirping of hundreds of swifts sweeping across the cavernous hall above our heads. The whole experience was genuinely mystical and surreal.
In truth, it was a spectacular adventure from start to finish. We used ropes once again, to climb out and exit the cave via the Great Wall of Vietnam, a calcite wall totaling 90m in height. This expedition required 28 porters, safety advisors, and guides, who really were the heart and soul of this fantastic journey. In the same way that the Sherpas of Nepal are instrumental to a climber’s success in summiting some of the highest peaks, the local porters of Son Doong are the true heroes of this multi-day caving expedition. These men all hail from Quang Binh, one of the poorest provinces in Vietnam, and come from a variety of working backgrounds such as farming, hunting, and logging. One thing they all have in common is their astounding ability to survive and thrive in the jungles of Phong Nha. All in all, seventeen porters, two chefs, one national park ranger, one porter team leader, five safety guide assistants, one lead guide and one British caving experts made up the team that took us on this remarkable journey inside the world’s largest cave.
The voyage was made even more poignant because our HER Planet Earth team was supporting a significant cause. This expedition aimed to raise awareness and funds for programmes that help the economic empowerment of women in rural Vietnam, strengthening their climate change resiliency. Thus, from the onset, thanks to this shared vision, our team was united in our purpose and humanity.
As we left the cave, my heart sank because a part of me wanted to run back to this precious Garden of Eden. Had we stepped back in time through a magical passage, deep inside the earth’s inner core? Or perhaps, taken a voyage to a lost world millions of years old? It felt that way to me. So much so that returning to my daily life took some time and readjustment. As we look back, the team and I feel privileged to have witnessed a glimpse of what the world must have looked like when dinosaurs roamed the earth and humanity was not even in its nascent stages. Somehow far from civilization’s hustle and bustle, everything seemed so much purer and simpler down there.
Photo credit: Sandra Lim, Oxalis Adventures & HER Planet Earth