Wake up at 7 am. Sunny! We had breakfast on the terrace under a perfect blue sky. The group was ready to leave around 8:20. It was a 9 km long trail to reach the top of the caldera, 700 meters above us.

Askja is indeed a large basaltic central volcano that forms the Dyngjufjöll massif. It is truncated by three overlapping calderas, the largest of which is 8 km wide and may have been produced primarily from subglacial ring-fracture eruptions rather than by subsidence. A major rhyolitic explosive eruption from Dyngjufjöll about 10,000 years ago was in part associated with the formation of Askja caldera. Many postglacial eruptions also occurred along the ring-fracture. A major explosive eruption on the south-east caldera margin in 1875 was one of Iceland's largest during historical time. It resulted in the formation of a smaller 4.5-km-wide caldera, now filled by Öskjuvatn lake, that truncates the rim of the larger central caldera. Especially in the eastern fjords of Iceland, the ashfall was heavy enough to poison the land and kill livestock. Ash, or tephra from this eruption was wind-blown to Norway and Sweden. The eruption triggered a substantial wave of emigration from Iceland.

The trail to reach the top of the caldera was quite steep at the beginning. But the landscape was breathtaking: due to perfect climatic conditions, we could see as far as Vatnajökull and Herðubreið mountain, which was quite unusual.





































We finally reached the top around 10 am and could discover the first lake, Öskjuvatn, offering its deep blue colour and a perfect reflection of the scenery. Its surface area is about 11 km². With a depth of 217m, it is the second deepest lake in Iceland after Jökulsarlon.





























After a short break to take some pictures, we walked towards the second lake, Viti, where the rest of the group was waiting for us.
Viti is a smaller explosion crater on the north east shore of Öskjuvatn, approximately 150 metres diameter. It contains a geothermal lake of mineral-rich, sulphurous, opaque blue water, which is maintained at a comfortable temperature for swimming. Swimming in these craters is not a good idea because carbon dioxide can accumulate on top of the water, making the swimmer pass out and drown.
Still, we could not miss the opportunity to swim in a volcano crater ! The smell was indeed very sulfurous, but the experience definitely worthwhile.

























Pierre then drove us back to the campground where we had lunch. We left Askja around 2:30 pm. The road came close to Herðubreið mountain, which is in fact a tuya. A tuya is a type of distinctive, flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet.
We then crossed several fords, and especially one which was quite deep. Both cars finally managed to cross it, but that was not the case of the swiss 4x4 following us. They should have read the sign with caution before entering the ford so fast... We called 112 and the rangers to rescue them.

















































The trail finally ended and we reached N1 road again ! Before arriving at Myvatn region, we made a stop at Námafjall. Námafjall is a high-temperature geothermal area with fumaroles and boiling mud pools. At a depth of 1000 meters the temperature is above 200°C. As is characteristic for other hot spring areas, there is a hot spring smell at Námafjall which is caused by the steam and the fumarole gas, such as hydrogen sulfide.



























We then drove to Myvatn campground, which is perfectly situated on the edge of the lake. We borrowed a BBQ at the front desk in order to cook salmon in foil with fresh vegetables and rice. Delicious!

After lunch, some of us headed to Myvatn Nature Baths, the local equivalent of Blue Lagoon without the white silica mud. Enjoying those warm baths from 9:30 to 11 pm was beyond words...
Was a quiet night after such a treat !