This is a place that you can't visit unless it's on a tour. I went with Tröllaferðir and it was unforgettable. This trip takes you close to the roots of a volcano called Katla. Katla is probably the most feared volcano in Iceland, having last erupted in 1918. Katla has for long played with fire and ice and on this tour you see the landscapes that Katla has formed and shaped. Visiting an ice cave is a great experience, inside the cave you can see layers of ash from previous eruptions.