On my sixth day in Iceland, I allowed myself to be lowered into a volcano. Lucky for me, Thrihnukagigur had fallen silent 4,000 years ago, so bubbling magma wasn’t an issue.

I stepped onto the swaying open-sided elevator suspended over the volcano’s opening, the climbing harness straps pulling tight against the backs of my thighs. The eight-foot-by-three-feet platform wiggled back and forth as each of the other five passengers stepped aboard. Gummi, our guide, unhooked us one by one from the guidelines that connected us to solid ground and reattached our carabiners to the elevator’s railing. A motor whirred to life, and we began the slow 400-foot descent.

The walls of the entrance narrowed, and the elevator’s sides scraped the wet, mossy surface. The colors embedded in the walls of the dark chamber told the story of an array of minerals: the brick red of iron, lemon yellow of silica, muted orange of sulfur, majestic purples of iron and copper.

“Get clear of the landing zone,” Gummi said as we neared the chamber floor. He tilted back his head, and the thin beam of his headlamp illuminated a constant shower of water drops and small stones that were dislodged when we squeezed through the entrance’s bottleneck. “Some of the rocks can be quite large,” he explained, “and sometimes, people drop their phones or cameras.”

Once safely away from the landing zone, I leaned against a large rock and took a deep breath.

“It’s something, isn’t it?” asked Gummi, who had pulled himself up on the boulder next to mine. I watched him as he looked around the immense vault, tall enough to accommodate the Statue of Liberty, wide enough for three basketball courts side by side, the entrance a mere twinkling star in the darkness above us. Despite what was likely his sixth or seventh visit of the week, not to mention the dozens of trips he’d made into the chamber over the summer, his eyes still sparkled with a sense of wonder.

And it was something. Some of my braver fellow travelers were picking their way around the edges of the chamber, their headlamps whipping this way and that. But I remained where I was, breathing in the cool, slightly musty air. The rock I leaned against grounded me in place.

My usual instinct when visiting somewhere new is to leave no stone unturned in my quest to learn and see everything. Here, though, I soaked this experience in without taking a step. The peaceful darkness, the quiet shuffling of footsteps on stone, the calming sanctuary of the chamber—it’s a place like no other, a natural cathedral.

Since Árni Stefánsson first descended into this chamber in 1974, people have wanted to explore this unintended place, to go somewhere that shouldn’t be. I can understand this drive now. Because this space should not exist, standing in the midst of the soft darkness, hearing the water drip, drip, drip from the entrance hole, I felt more alive than I thought possible.