Surtshellir

Listen for a moment. Up here on the lava field, the wind moves over moss and broken rock, and there is almost no other sound. Then you step toward the dark opening in the ground, and the air changes. It turns cold and still. It smells of wet stone. Water drips somewhere below. You are standing at the edge of Surtshellir, one of the best-known lava caves in Iceland, cut deep into the Hallmundarhraun lava field in the highlands of west Iceland.

First, a word about the name. Surtur is the fire giant of Norse mythology. In the old poems, he rides out at the end of the world with a flaming sword and sets the earth alight. People who found a huge black tunnel inside a field of cooled lava reached for the most fitting figure they knew. To them, this place looked like the giant's own hall, hollowed out by fire.

In a sense, they were right about the fire. Surtshellir is a lava tube. Geologists date this lava field to roughly the tenth century, around the time the first Norse settlers were building farms in the valleys below. The eruption came from vents to the east, near the Langjökull ice cap. Rivers of molten rock ran west across the land, and some of those rivers flowed beneath a crust of their own making.

Here is how a tube like this forms. The surface of a lava flow cools first and hardens into a roof. Underneath, the hot lava keeps moving, sealed inside its own insulated pipe. When the eruption ends, the liquid drains away downhill. What remains is an empty tunnel, sometimes many metres high. Surtshellir is well over a kilometre long, and it connects with a neighbouring tube, Stefánshellir, to form one of the longest cave systems in the country.

Look up as you move along the edges. In several places the roof has fallen in. These collapses form great open pits, and they work like skylights. Grey daylight falls through them onto heaps of broken basalt below. Moss and small ferns grow on the rims, where moisture gathers and the wind cannot reach. Between the skylights, the tunnel runs into full darkness, and the temperature drops even further.

Now the human story, which surprises most visitors. Iceland has a long tradition of outlaws, people sentenced to live outside the law and outside society. Old written sources and later folk tales connect Surtshellir with a band of such men. One medieval saga, known as the saga of the cave men, tells of outlaws who lived here and raided farms in the district. How much of that tale is history and how much is storytelling, nobody can say for certain.

But the cave itself holds real evidence. Deep inside one section, early explorers found piles of animal bones, many of them from sheep and cattle. There are also traces of stone walls and simple structures built inside the tube. This part is often called the fortress cave. Someone did shelter here, and someone ate a great deal of stolen or hunted meat. Standing in the cold, it is hard to imagine a whole winter spent in this darkness.

Locals also tell a darker tale. According to one popular story, farmers from the surrounding valleys finally gathered and hunted the outlaws down. Treat that as folklore. What is better documented is that the cave drew learned visitors from early on. In the eighteenth century, the Icelandic naturalists Eggert Ólafsson and Bjarni Pálsson explored and described it during their famous survey of the country. Their reports helped make the cave known far beyond the district.

That fame came at a cost. Lava tubes are fragile places. Over the centuries, visitors broke off formations and carried away small pieces of the cave as souvenirs. In the colder parts, ice once formed delicate columns and sheets on the floor, and much of that has been damaged. Today, some sections are protected and may be closed to entry. Please respect any barriers or signs you see. They exist because the damage here cannot be undone.

If you do go underground, think carefully about your feet. The floor is not a smooth path. It is a field of jagged, loose boulders, many of them fallen from the ceiling. In places they are slick with water or ice, even in summer. Move slowly. Test each step. Keep three points of contact when you climb. Without your own light, you will see absolutely nothing once you leave the skylights behind.

Switch off your torch for a few seconds, if you feel safe doing it. The darkness here is total. There is no glow from a city, no reflection from the sky. Your eyes do not adjust, because there is nothing for them to adjust to. In that silence, you can often hear the slow drip of meltwater and your own breathing. It is one of the quietest places most travellers will ever stand.

Back at the surface, take time to read the landscape. The lava field around you looks like a frozen sea of black and grey rock, softened by thick green and silver moss. That moss grows extremely slowly and tears easily, so stay on the marked track. On a clear day, you can see the white shoulders of the glaciers to the east. They sit near the source of the very eruption that built this tunnel.

This is also a remote place. The nearest settlements are farms and small communities in the valleys of Borgarbyggð, and services out here are few. The road is gravel and conditions change quickly with the weather. Many visitors combine this stop with a guided visit to another lava tube in the same field, where walkways and lighting make the experience easier. Surtshellir is different. It is rougher, wilder, and much closer to how the first explorers found it.

Before you walk away, look once more at the opening in the ground. A thousand years ago, this was a river of fire. Later, it became a refuge, a legend, and a subject for scientists. Now it is quiet again. Feel the cold air rising from below, and the wind on the lava field around you. Then follow the track back across the moss, and notice how small the entrance looks from just a short distance away.