Taking a tour through the world's biggest cave
Some 300 metres below the surface of the surrounding land lies a beach of the finest sand. Clouds hang low.
When you brush your teeth on a ledge above the rocky chasm, you can hardly see the jungle down below, where the white mists are swirling in the morning air.
This is a view into the most voluminous cave in the world. Eight kilometres away by an underground path is the other end, the “Vietnamese Wall.”
The Hang Son Doong lies in the Phong Nha Ke Bang National Park in central Vietnam, near the border with Laos. Within the cave a river flows. It rages at some points and is gentle and sometimes not even visible at others.
After every rainy season it breaks new ground through the stony tunnel. Where it once flowed, sand remains behind – and there’s a lot of sand. The cave is so gigantic that it forms its own clouds.
“Many of its really large caverns have their own cloud systems,” says Howard Limbert.
Limbert is a cave explorer. The Briton has been a regular visitor to the Phong Nha area over the decades and the locals have developed an affection for this westerner who loves their caves so much.
Back in 1990 a man named Ho Khanh told Limbert that he had found a new cave in the jungle. It was pretty big, he thought, but he wasn’t sure.
Only in 2009 did the men again find the entrance, and Limbert gradually measured the cave. Quickly it became clear: there, hidden in the jungle, was the most voluminous cave in the world.
Hang Son Doong is 8.9 kilometres long, The deepest point lies 490 metres underground. The largest hollow point has a roof 200 metres high – large enough to fit a cathedral inside.
“There are many, many longer caves,” Limbert admits. “But they are generally very, very narrow. Son Doong is simply gigantic in places. Any other cave in the world would fit inside it!”
After discovering the cave, Limbert become a professional spelunker and now works for Oxalis, a tour company that organises trips through the caves of the national park. The tour lasts six days, and the 224 tickets for 2014 that the provincial government allows to be sold annually sold out in two days last October. Only Oxalis can sell the tickets.
Karst rock and primal forest shape the national park, which Unesco listed as a world natural heritage in 2003, partly for its many caves. The entrance to Hang Son Doong is via another cave, the Hang En.
Some 14 porters take all the food, tents, sleeping bags and baggage on their backs. And two cooks are in tow.
The team moves at its own tempo, but it is mostly near to the tourists.
You have to duck at the entrance to the world’s most voluminous cave and it’s impossible to see really deep inside. You can’t really see deep inside it either.
“It’ll now be a big tricky. We have to descend about 100 metres. Buckle up and I promise you, nothing bad can happen,” Limbert tells the group.
After the descent, fully roped up, it’s not too far to the camp. From afar, the tents look like a line of helmets laid on a beach of fine golden sand. The porters have put them up.
“Would you mind coming a little over here,” Limbert says placidly, beckoning an exhausted tourist closer. Only when she stands next to him, does he tell her why. A minute ago she was standing on the very edge of a lofty precipice without knowing it.
The 100-metre cliff towers above the camp. Below is the roaring river.
The first sinkhole is nearby so the camp enjoys daylight.
It is a funnel-shaped cavity that was created a few million years ago when the river water continually ate through the limestone.
The cave grew and grew, the roof over the gigantic hollow was unable carry its own weight, and it collapsed. It must have been like an earthquake. At the bottom of the funnel is a miniature green jungle.
Even more spectacular is the second cave-floor jungle, which is about half a day’s march from the first: here too the roof has collapsed.
The hikers’ feet sink in some areas into powdery ground made of a strange sand.
“Not sand,” says Limbert. “It’s ancient bat guano.”
On the fourth day Son Doong shows once again what it can provide. At about the 8-kilometre mark, the “Vietnamese Wall” towers steeply out of a green-blue subterranean lake. The group paddles with rafts to the 80-metre-high formation made of soft brittle stalactite.
The wall has grown out of a great hollow in the cave. The roof here is 200 metres high and can’t be seen, even with very strong torches. On top of the wall, there’s just a couple of hundred metres left until the exit.
But only professionals can climb the “Vietnamese Wall,” so the tourists turn around and take two nights and almost two days to reach the top of the wall by the longer route.
Two small buses from Oxalis wait outside on the road with ice-cold beer and cola drinks. People celebrate, wheeze, and take off wet socks and leeches from their feet. The ascent was hellish.
Only Phan Van Thin, the Vietnamese guide, does not wheeze, but springs excitedly into a new bus.
“Brand new!” he yells. Actually, spanking brand new with pale leather seats. A couple of minutes later, eight rear ends covered in red mud pile into the leather. The driver closes the door from outside, steps into the front and a tourist, a doctor from Hawaii, begins to name the seven wonders of the world.
If you go
_ Hang Son Doong is located in Phong Nha-Ke Bang National Park, Quang Binh Province, Vietnam. Dong Hoi, the capital city of Quang Binh Province, is about fours hour on the bus from Hue in Central Vietnam.
_ Oxalis Adventure (www.Oxalis.com.vn) is the only operator with permission to run tours to Son Doong Cave. For more information about the cave, visit http://WHC.Unesco.org/en/list/951 and www.PhongNhaKeBang.vn/en.