Krafla’s most impressive, and potentially most dangerous, attraction is the Leirhnjúkur crater and its solfataras, which originally appeared in 1727, starting out as a lava fountain and spouting molten material for two years before subsiding.
In 1975, the Krafla Fires began with a small lava eruption by Leirhnjúkur, and after nine years of on-and-off action Leirhnjúkur became the ominous-looking, sulphur-encrusted mudhole that tourists love today. The earth’s crust here is extremely thin and in places the ground is ferociously hot.
A well-defined track leads northwest to Leirhnjúkur from the Krafla parking area; with all the volcanic activity, high temperatures, bubbling mudpots and steaming vents, it's best not to stray from the marked paths.
