Vietnam Cave

Conquering an Infinite Cave

There’s a jungle inside Vietnam’s mammoth cavern. A skyscraper could fit too. And the end is out of sight.

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,Past the hand of dog, watch out for dinosaurs,” says a voice in the dark.

I recognize Jonathan Sims’s clipped, British military accent but have no idea what he’s talking about. My headlamp finds him, gray muttonchops curling out from beneath his battered helmet, sitting alone in the blackness along the wall of the cave.

“Carry on mate,” growls Sims. “Just resting a buggered ankle.”

The two of us have roped across the thundering, subterranean Rao Thuong River and climbed up through 20-foot blades of limestone to a bank of sand. I continue alone, following the beam of my headlamp along year-old footprints.

In the spring of 2009, Sims was a member of the first expedition to enter Hang Son Doong, or “mountain river cave,” in a remote part of central Vietnam. Hidden in rugged Phong Nha-Ke Bang National Park near the border with Laos, the cave is part of a network of 150 or so caves, many still not surveyed, in the Annamite Mountains. During the first expedition, the team explored two and a half miles of Hang Son Doong before a 200-foot wall of muddy calcite stopped them. They named it the Great Wall of Vietnam. Above it they could make out an open space and traces of light, but they had no idea what lay on the other side. A year later, they have returned—seven hard-core British cavers, a few scientists, and a crew of porters—to climb the wall, if they can, measure the passage, and push on, if possible, all the way to the end of the cave.

The trail disappears before me into a difficult pile of breakdown—building-size blocks of stone that have fallen from the ceiling and crashed onto the cave floor. I crane my head back, but the immensity of the cave douses my headlamp’s tiny light, as if I were staring up into a starless night sky. I’ve been told I’m inside a space large enough to park a 747, but I have no way to know; the darkness is like a sleeping bag pulled over my headI switch off my headlamp just to feel the depth of the darkness. At first there is nothing. But then, as my pupils adjust, I’m surprised to make out a faint, ghostly light ahead. I pick my way through the rubble, almost running from excite­ment, rocks scattering beneath my feet and echoing in the invisible chamber. Traversing up a steep slope, I turn a ridge as if on a mountainside and am stopped in my tracks.

An enormous shaft of sunlight plunges into the cave like a waterfall. The hole in the ceiling through which the light cascades is unbelievably large, at least 300 feet across. The light, penetrating deep into the cave, reveals for the first time the mind-blowing proportions of Hang Son Doong. The passage is perhaps 300 feet wide, the ceiling nearly 800 feet tall: room enough for an entire New York City block of 40-story buildings. There are actually wispy clouds up near the ceiling.

The light beaming from above reveals a tower of calcite on the cave floor that is more than 200 feet tall, smothered by ferns, palms, and other jungle plants. Stalactites hang around the edges of the massive skylight like petrified icicles. Vines dangle hundreds of feet from the surface; swifts are diving and cutting in the brilliant column of sunshine. The tableau could have been created by an artist imagining how the world looked millions of years ago.

Jonathan Sims catches up with me. Between us and the sunlit passage ahead stands a stalagmite that in profile resembles the paw of a dog.

“The Hand of God would be just too corny,” he says, pointing at the formation. “But the Hand of Dog does nicely, don’t you think?”., ,,,,