Manjanggul Caves

When I was a boy, I was entranced by Jules Vernes’ Journey to the Center of the Earth. There was something deeply alien about the idea that just beneath my feet lay a world that had never seen sky or sun.

I got older and found other books: Middle Earth’s Mines of Moria, Edgar Rice Burroughs Pellucidar, CS Lewis’ Narnian adventure in The Silver Chair. By then I knew that a vast underground world wasn’t really possible. But I still felt a romantic longing to adventure in one of the deep places.

Then we moved to Jeju.

South Korea’s island paradise is the result of a series of violent eruptions tens of thousands of years ago. The central peak, Hallasan, stretches two kilometers high. And it’s just the most prominent in a chain of over three hundred and sixty volcanoes.

As a result of this tectonic violence, Jeju is riddled with lava tubes, deep caves that run for thousands of miles below the surface. The system is a UNESCO world heritage site, home to an ecosystem that is almost unique in the world.

Over the summer, we explored a small piece of it with the help of some friends. Manjanggul Cave lies on the eastern part of the island. First surveyed by a local teacher and his grade school class (imagine THAT permission slip), it’s five kilometers long, and almost entirely walkable. Some of the lower levels, closed to the public, contain the largest bat colony in Korea, as well as unusually big spiders, newts, and other critters.

But reading a description isn’t the same as walking down into the darkness. The day we went was blisteringly hot, and humid in a way only an island can really pull off. Standing at the entrance to the cave, the long stairs seemed to stretch down into a well.

Above ground, it was 35C, or about 95F to you Americans. But just climbing down to the first landing, the temperature plummeted. It was like stepping into a cool, dark basement. The humidity didn’t go anywhere. If anything, it got worse. But the air became a steady 12C, 53F. According to a sign near the entrance, the cave stays right around that temperature year round.

Only about a kilometer of Manjanggul is open to the public. The floor is a mix of hardened lava and wooden walkways. Here and there we found signs talking about how the cave was formed, or what certain features meant. It was all very informative and quite well done.

But the whole time, I couldn’t shake the knowledge that tons and tons of rock hung just above my head. The tunnels were dark, the footing difficult. Inky black water pooled everywhere.

And there was always that shiver, waiting for a giant cave spider to drop onto my head. It didn’t help that the porous rock constantly rained, so I often felt the soft tap of something brushing the back of my neck. At one point, the eerie atmosphere got to us, and to lighten the mood, we started talking about what it would be like to find zombies and other horror movie classics, down in the dark.

We were not very smart.

The walk ended at a massive lava chimney, stretching a dozen meters from the floor to a hidden chamber in the ceiling. It was a bit like stepping into a Jules Verne tale. Well, if Journey to the Center of the Earth featured a lot of people taking selfies.

There were no morlocks. In fact, there were hardly any creatures in that part of the cave at all—they understandably avoided tourists, staying in the quieter parts, the deep parts. And though the museum featured a spider as large as my head, we saw nothing living but the tourists.

Nevertheless, if you’re coming to Jeju, I highly recommend it.

-Sam

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