Eldgjá Canyon

Eldgjá, the "fire canyon", is the largest volcanic gorge on Earth — a vast fissure in the Fjallabak highlands and part of the Katla volcanic system. It opened around 934–939 in the largest lava flood in recorded history, burying hundreds of square kilometres of land. About midway along, the waterfall Ófærufoss drops over the rim in two tiers. Reaching it means fording unbridged rivers on the F208, so it is a summer-only, 4x4-only place.