We stayed overnight at the campground in Ásbyrgi — “shelter of the Æsir,” the Norse gods — a horseshoe-shaped canyon in northeastern Iceland and part of Vatnajökull National Park. The canyon stretches roughly 3.5 kilometers and is enclosed by basalt cliffs rising nearly 100 meters, high enough to create a sheltered microclimate that supports dense birch woodland.

That woodland is a relic: when Norse settlers arrived around 870 AD, birch forest covered an estimated 25–40% of Iceland. Within a few centuries it was nearly gone, cleared for timber and charcoal, with sheep finishing the job by grazing down any seedlings that tried to regrow. Ásbyrgi’s towering cliffs made the trees here harder to access and less practical to clear, which is likely why this pocket of woodland survived when the rest of the island was stripped bare.

The canyon itself was carved by catastrophic glacial outburst floods released from the Vatnajökull ice cap. These events discharged water at volumes that dwarf any modern river, cutting through the basalt bedrock and producing the canyon’s characteristic U-shape. A central rock island called Eyjan (“the island”) divides the canyon into two branches. At the innermost end sits Botnstjörn (“the innermost pond”), fed by groundwater percolating through the cliff walls — its stillness a direct contrast to the violence that created it.

The canyon’s shape invited an obvious legend: Norse mythology attributed it to a single hoofprint left by Sleipnir, Odin’s eight-legged horse. The name Ásbyrgi — shelter of the gods — fits the same tradition. Before glaciology provided an explanation, the horseshoe outline needed one, and the legend predates the science by centuries. It remains the more memorable account.