Posted March 31, 2014 by Steve McDonald in Adventure

Photo Travelogue: The Biggest Darkness (An Expedition to the Largest Cave Chamber on Earth)


When I was a little fat kid and my favorite computer game was Microsoft Encarta, I promised myself that one day I would visit the Sarawak Chamber in Borneo. I wanted to see the biggest darkness. I wanted to stand before the largest cave chamber on earth—large enough to fit ten Boeing jets nose to tail. But mostly I just wanted to play with ropes and helmets. My mother had recently shown me a documentary film in which Brendan Frasier went caving and found a lost jungle of dinosaurs and mole people, and though I figured he was lucky, I was hoping for that.

So for this week’s Photo Travelogue I’m taking you there, on a twelve-hour advanced expedition deep into the earth’s crust, to an alien and unknown world where only the most intrepid dare wander.

But first I’m going to tell you about my bizarre and unwholesome fetish…

Ready kids??

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Behold! The most wonderful, sexy inanimate object in the natural world…



If you don’t know why I’m so excited about mineralized seashells crushed underwater millions and millions of years ago, please, allow me to explain my nerd boner.

Unlike other boring, stupid rocks, limestone is porous and soluble in water, meaning that not only does rain flow through it like a sponge, but it dissolves the limestone like salt!!

So the fuck what?

That means that the rain acts like a carving knife, making limestone responsible for some of the most breath-taking geological formations on earth…

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Like the phallic towers of Cappadocia in Turkey…

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…Or the karsts of Ha Long Bay in Vietnam

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…Or the peaks of Yangshuo in China

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Here at Gunung Mulu in Borneo, rain has whittled the limestone into sharp pinnacles, making it the worst place in the world to parachute.

But to glimpse the most spectacular limestone formations, one must journey underground…


Before we start our caving expedition proper, I should probably explain how the caves of Gunung Mulu were formed… But this isn’t a science blog and I know that if I write anything more academic than Dora The Explorer, it will send half of you dipshits scurrying back to Facebook. So worry not! I’ve chewed and digested all the big science stuff and will now vomit it into your mouths like a mother bird to her chicks, so you don’t have to do any abstract thinking.

Pretend you have a giant sugar cube the size of a football field. Now climb on top of it with a cup of water and dump it in the exact middle. Repeat this process 20 million times. Like the sugar cube, limestone dissolves in water (albeit at a much slower rate). As cracks and fissures fill with rain, they bore holes into the thick limestone shelf. Once the water reaches a more resistant layer of limestone, it alters its course and a river is formed, creating the cave.

But what makes the caves of Borneo so special is that there’s something else powerfully and invisibly at play…

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Let’s do the sugar cube thing again, but with one exciting twist! Instead of filling your cup with water, find a bucket of Mafia-strength, hooker-dissolving Hydrochloric acid.

Borneo is swathed in thick tropical rainforests, and when rain is exposed to high levels of CO2 (like in jungle soil), it turns into corrosive carbonic acid. Carbonic acid is much weaker than Hydrochloric acid, but as you’re about to see, it eats through limestone like cupcakes.

In just a few million years, rain has carved central Borneo into an epic network of underground tunnels, boasting soaring cathedral chambers and forests of stalactites and stalagmites. But the cherry on top are the geomorphic giants like Deer Cave—one of the most spectacular natural wonders in Asia…

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Deer Cave is so massive that you could fly a Boeing jet through it. It was believed to be the largest cave passage on the planet until 2009, when a slightly larger passage was discovered in Vietnam.

Deer Cave still clings to the spotlight, however, as the stage for one of the most dramatic animal gatherings on earth…

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There are an estimated 3 million bats living in Deer Cave, inhaling on average 30 tons of mosquitoes per night—though I can’t imagine why or how any normal person would measure that. Each sunset, millions of bats emerge from the cave en masse, swooping and swarming in spectacular aerial displays. The phenomenon attracts tourists from around the world, who seem eager to greet the shrieking rain cloud of guano.

But for those who wander into the caves, there are more bizarre and terrifying creatures waiting in the dark…

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“Don’t touch the Hairy Murry! It will kill you!” Park Ranger Syriah flailed her arms.

We had barely passed through the mouth of Deer Cave when I bent over to touch the giant insect.

“Poison! Poison!” she cried.

It seemed miraculous to me that life can flourish in a place without sunlight, where the only available foods were wet rocks and clay.

The key to life, it turned out, was just above my head, being showered out of a bat’s rectum.

Rich with nutrients from the outside world, guano provides food for cave insects, which provides food for insectivores, which provides food for bigger, stranger things—albino scorpions, eyeless crabs, echo-locating swiftlets, giant venomous centipedes, snakes with infrared vision. Through this process, the great Circle of Life emerges from a foul heap of bat crap.

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While Deer Cave is open to the public, the more difficult caves require a permit—which is only granted to experienced cavers.

“Sarawak Chamber is very dangerous and many people get hurt,” explained Syriah, handing me my helmet and rope. “You’ve been caving before?”

“Of course!” I scoffed. “A few times in America. But it was very different from this,” I explained, because those times were make-believe and I’d never been caving.

“Excellent,” she nodded. “But we still require all cavers to demonstrate their skills first.”

“Sure! How do I do that?”

By signing up for more expensive caving tours. That’s how. If I wanted to glimpse the biggest darkness, I needed to pass a test-expedition…

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My friend Leon and I scanned the menu of expeditions. “What’s the coolest cave?” I asked Syriah.

“Clearwater!” she fired. “It’s the biggest cave system in the world by air volume!”

“What’s it like?”

“Well, it’s eight hours underground. First you climb up big boulders in the dark for two hours. They are very sharp and they cut your hands. Then you rappel down a rope and crawl over slippery mud that smells like guano.”

“We’re crawling in guano.”

“Exactly! But then you reach the first squeeze and you have to get down a ten-meter crack in the rock using only your hands. It’s extremely tight. You can’t even turn your head! And at the bottom, there’s a beautiful chamber of cave formations. So, so beautiful! Stalactites, stalagmites, flowstones… And many insects. They attack your face.”

“Wow, this all sounds great.”

“Then there’s another tight squeeze. It’s very hot. Then the passage spits you in an underground river and you have to wade for 2km with all your clothes on. It’s the best.”

“Sounds it!”

“Much more fun than Sarawak Chamber.”

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Clearwater Cave was just as thrilling as Syriah promised—though she neglected a few highlights.

Like the part where we had to traverse a cliff face covered with venomous spiders.

Or the part where we were never provided harnesses.

Or the part where Leon and I laughed at a dick-shaped stalagmite and our guide went ballistic, shouting that we’d insulted the cave spirits.

Or the part where we had to climb over painful speleothems for eight hours.

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Speleothems are cave formations made from calcite, derived from dissolving limestone. By observing speleothems—along with the sediments, minerals, textures, wall markings, and even dust—geologists can read a cave like a history book; each clue tells tales of water movement and climate change, coloring in the tectonic backstory of our planet.

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The deeper we descended underground, the more extraterrestrial the speleothems appeared—from stalactites and columns to alien-looking egg shapes and spiny coral formations—until Clearwater felt less like a cave and more like a high budget laser tag arena.

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To reach Sarawak Chamber, the largest cave chamber on earth, the twelve-hour journey is broken into three legs.

First you must trek for three hours in the jungle, frequently getting lost, fording rivers, and slashing along hog paths with a machete. Eventually you reach the mouth of the cave—a large crevasse in the mountainside, from which a river flows.

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The second leg involves wading upriver through a narrow underground canyon. And by “wading,” I mean splashing and pouting through freezing, waist-deep torrents, tripping over boulders in the dark, and swatting at the buzzing miasma of insects around your headlamp. Occasionally you must scramble over waterfalls, and at one point you get to accidentally fall off a rope traverse and crash into an icy pool, before apologizing and splashing up current to the opposite bank.

This portion lasts several hours and concludes with your guide casually instructing you to scale a vertical rock wall out of the rapids.

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The final stretch to the Sarawak Chamber requires a long, tedious trek over guano-plastered scree. As you climb, Sarawak’s massive antechamber opens up before you, hemmed by soaring, megalithic walls of limestone.

After what feels like hours, you arrive at a non-descript pile of boulders, where the guides announce that you’ve reached the lip of the Sarawak Chamber…

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Park Ranger Harvey’s flashlight danced across the arch of the entrance as we peered into the chamber—an impenetrable ocean of black. This would be the end of our journey—to venture any further was suicide; our high-powered LEDs were no match for the vastness of Sarawak Chamber, and without any point of reference in the dark emptiness, we were certain to get lost.

“We can’t see anything,” muttered my friend Grant. “What a piece of shit!”

Clearly Grant had unrealistic expectations of the biggest darkness. He simply didn’t realize the impossible scope of Sarawak—but he wasn’t to blame for that.

I can’t understand why Boeing jets is the standard unit of cave measurement. Who the fuck is lining up ten jets in a cave? Who is lining up ten jets anywhere? Unless you happen to collect airplanes, this analogy is as abstract as me saying the cave is 656 Honey Boo Boos wide.

So, for the purposes of edification and entertainment, allow me to convey its enormity in more inventive terms.

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To expect a headlamp to work in the Sarawak Chamber would be like pointing a flashlight across seven football fields and expecting to find cheerleaders on the other end. The chamber measures an astonishing 2,296 feet long, 1,312 feet wide, and 229 feet high—flaunting the same cubic volume as 7,840 Olympic-sized swimming pools. That’s enough space to warehouse 757 Statue of Libertys, if she’d just lower her goddamn arm. Although the height of the chamber isn’t as monumental as its breadth, you could still stack 3 White Houses, 35 Michael Jordans, or 63 Rachel McAdams’ foreheads.

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We decided to switch off our headlamps and experience the darkness for a few minutes. I didn’t expect what happened next.

Absolute darkness is as fascinating as it is rare; even if you can’t see, typically there are still a few lumen present. But in the complete absence of light, the brain falls into somersaults. Confusion sets in. It becomes difficult to tell if your eyes are open or closed. You can sense an alarm bell in the back of your mind as your body starts firing adrenaline. And then, as if someone is cranking up a volume knob, your hearing kicks in.

The cave that seemed silent was now roaring with noise—the clicking of bats, the flutter of swiftlets, the distant groan of the river, the tapping of insects feeling through the dark, scuttling over rocks that haven’t seen sunlight since the dawn of our planet.

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I have seen the biggest darkness. I have stood before the largest cave chamber on earth.

I wanted to conclude this Photo Travelogue with a shot of the Sarawak Chamber, but as I stood before it with my headlamp, that seemed laughable.

But perhaps there was another way to conquer its darkness…

Balancing my camera on a rock, I cranked the Xenon flash lamp to a blinding +2.0f/30,000 lumen and switched the Long-Exposure setting to thirty seconds. I then asked everyone to train their high-power LEDs into the chamber—an insane total of 96,000 lumen—enough light to pop a bat’s head off—before pressing the shutter.

It took the camera a minute of rendering before an image flashed across the screen. I stared at it for a moment as a smile crept across my face.

It was the perfect representation of the largest cave chamber on earth, a fine finale for our photographic expedition:

It was a snapshot of 96,000 lumen being swallowed in the invincible blackness of Sarawak Chamber, the biggest darkness.

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Backpackology has a Facebook Page and YOU WILL LIKE IT. Or else.

For more fun facts and pretty pictures, journey the Silk Road across China in the Photo Travelogue “Silk Road Ramblings: Lost Empires, Gobi Fugitives, and the Secret Meth Habit of Marco Polo

Or delve into the world of nomadic eagle hunters in the Mongolian Photo Travelogue “A Steppe Too Far: Eagle Hunters, Cultural Darwinism, and Getting Banned in Kazakhstan

This photo travelogue would not have been possible without the contributions of my travel buddy Anders Lundell. Thank you for lending this post your excellent lens and even more excellent eye.

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Steve McDonald

Writer and photographer. Adventurer and didactic prick. Guru of globetrotting, sensei of savings. PhD in ADHD. Staunch opponent of the mundane. Avid fan of sunrises, playing with fire, and pretending to know what I’m talking about. Casual existentialist. Bus stop gypsy. Dirty jeans, plastic sunglasses, whimsical death wish. Rudyard Kipling on mushrooms. Smells of goat.