Not far from Seljalandsfoss, the road to Þórsmörk (4WD required) hides one of the most thrilling and adventurous scrambles to a waterfall along a river and through an ancient moss-covered canyon called Nauthusagil. Although the walk through the ravine is short (roughly 1.5km, one hour out and back), you have to be reasonably steady on your feet (unless you don't mind getting wet). It requires walking planks, navigating and hopping dozens of pebbles and boulders, using precarious ropes (optional) and traversing walls with chains.
Those with less balance and fitness may find it easier to wear rubber boots and just walk through the river at times. It's about 10km north of Gljúfrabúi with a parking place.
