Highland Caldera
Askja is a composite caldera complex in the Dyngjufjöll Mountains of the central highlands. The volcano rises to 1,519 m, and the largest caldera contains a deep crater lake (Öskjuvatn). This otherworldly landscape served as a training ground for Apollo astronauts preparing for the Moon landing.
In 1965 and 1967, NASA sent Apollo astronauts to Askja to train for the Moon landing. The lunar-like landscape, volcanic craters, and basalt formations provided an ideal environment to practice geology and rover operations before the historic Apollo 11 mission.
Víti (meaning "Hell" in Icelandic) is a stunning turquoise-blue crater lake formed during the 1875 eruption. The geothermal-heated water reaches temperatures of 20-60°C, creating a dramatic contrast against the dark volcanic rock.
While swimming in Víti has been popular, always check current conditions and restrictions. The path down is steep and can be slippery. Weather can change rapidly in the highlands. Never swim alone.
Askja's most famous eruption occurred on March 29, 1875, one of Iceland's most powerful and consequential volcanic events.
An explosive eruption ejected huge volumes of tephra. Ashfall darkened daytime skies across eastern Iceland and deposited ash as far as Sweden, Norway and Germany. This catastrophic event led to crop failure and livestock deaths, triggering a significant wave of emigration from Iceland.
Since 2021 the caldera floor has uplifted ~70 cm, and seismic swarms (e.g., March 2024) indicate magma accumulation. Scientists monitor the region for a possible new eruption.
Askja is one of Iceland's most remote and challenging destinations, accessible only in summer via F-roads requiring 4WD vehicles.
Due to the challenging access, many visitors choose guided super jeep tours or bus tours from Mývatn or Akureyri. These tours handle the difficult driving and provide expert knowledge about the area's geology and history.