We returned to Mývatn for a day, filling our time with a walk around the east side of the lake. We passed the eerie fissure Grjotagjá, which is filled with very hot water. It’s in an underground cavern, and thin shafts of sunlight from above show the steam rising from the surface of the pool. It used to be a good temperature for swimming, but soon after the most recent eruptions at Krafla began, it heated up to over 60° C.
From Grjotagjá, we walked to Hverfjall, another big crater, this one made entirely of loose gravely rock. It takes a good amount of exertion to climb up the slope as it gives way beneath you. It certainly brings home the meaning of 'one step up, two steps down'. The crater has no lake inside, instead exhibiting a large central mound. Although you are prohibited from walking down into the crater, the mound in the middle is covered in ridiculous graffiti, of the "Colchester boys woz ere, 5/4/95" variety.
After the exertion of climbing this slagheap of a crater, and facing fearsome winds at the top, this was something of a letdown. But not to be deterred, we walked round the rim and down the other side, and on through Dimmuborgir, an amazing lava formation. Several thousand years ago, a huge lava lake formed here. After cooling down for some time, and partially solidifying, an ancient lava flow that had been damming it gave way, allowing the liquid left to pour out. Left behind were many hundreds of towers of contorted lava. Natural arches and caves abound, and many fascinating trails can be followed.
We wandered through Dimmuborgir for a while, then walked back to our campsite by the lake shore. Here we saw a quite fabulous sunset, which bathed the hills and houses in a gorgeous orange glow. The sun sank beneath the opposite shore of the lake leaving behind a burning sky, which was mirrored in the rippling waters of Mývatn. However, the feelings of deep humanity this inspired in us were quickly dispersed by the arrival of the midges, and we repaired to the tents in a hurry, ready for an early rise the next day.