Visit the lava and the mountains around Askja.
The lava, wilderness and tall mountains around the Askja volcano make it an unforgettable landscape. This active volcano in the Ódáðahraun area, north of the Vatnajökull glacier wasn’t explored until the 19th century, as the region is only accessible for a few months of the year. It wasn’t until an epic eruption in 1875, resulting in poisonous ash killing off livestock in Iceland’s Eastfjords and making its way to Norway and Sweden, that the volcano became widely known.
Askja was formed during a period of intense volcanic activity when a magma chamber beneath it emptied back into the earth during successive eruptions, causing the floor of the crater to sink. The resultant valley filled with water to form Lake Öskjuvatn, which at 220 metres deep is the deepest lake in Iceland.
Next to Öskjuvatn is the smaller, green crater lake called Víti. Technically you can go swimming in the warm waters of Víti, although the slopes surrounding the lake can get slippery in wet weather. This makes it difficult to climb down and up, so anyone who decides to swim here does so at their own risk.View Central Highlands of Iceland