Setting eyes on Askja, an active volcano - the last eruption was in 1961 - in the middle of the lava fields at 1 515m altitude, will most definitely be one of the highlights of your time in Iceland. It is truly magical when you see the two lakes that fill the 45km2 caldera: on one side, Öskjuvatn, with its clear, sapphire-blue waters; on the other, Víti, a small crater lake, with hot and milky turquoise waters, which travellers take pleasure in sliding into.