The unusual geographical formations of Mývatn testify to the region's explosive past; in the 1700's this area was subjected to a series of volcanic episodes so violent that they have become known as the Mývatn Fires. These eruptions occurred along huge rifts and have created an alien landscape of rich red oxides, pyroclastic flows and steaming lava fields.
Around Mývatn Lake the land has cooled, creating a wetland oasis, popular with walkers and runners alike. However, this area has lost none of its geothermal productivity; a short drive to the north the active Krafla volcano adds to the Leirhnjúkur lava fields. The ground here is crisscrossed by hidden thermal fishers and steaming mud baths that make stepping off the path dangerous.
This is an area scattered with volcanic deposits, from the black tephra rings at Hverfjall Crater to the startling blue lake that has formed at Viti. Hiking to these sites can be hard work, but the panoramic views at the top are worth the effort.
Meanwhile, the Mývatn Nature Baths and the cool subterranean lava cave at Lofthellir offer a quieter picture of this diverse volcanic region.