Holuhraun

The Holuhraun eruption opened north of Vatnajokull in August 2014 and ran until late February 2015, producing something over 80 square kilometres of lava - the largest flow in Iceland since the Laki eruption of the 1780s - fed by magma that travelled underground for tens of kilometres from beneath the Bardarbunga volcano, whose caldera floor sank by tens of metres as it drained. Because the fissure was in the open desert rather than under ice, there was little ash and no significant international disruption, but the sulphur dioxide output was very large and air quality warnings were issued across the country for months. The field is now open, black and almost untouched.

What you actually see

• Over 80 square kilometres of lava - the largest Icelandic flow since the 1780s.
• Magma from Bardarbunga - travelled underground for tens of kilometres.
• A caldera that sank - Bardarbunga's floor dropped as the chamber drained.
• Sulphur rather than ash - the reason air quality, not aviation, was the problem.

When to go

July to early September, when the highland tracks are open. A full day.

Honest expectations

This is deep-interior driving with unbridged rivers and no services; most people reach it on an organised trip from Myvatn. The lava is sharp and unstable and gas can still be present in hollows. Weather closes the tracks at short notice.

Nearby

Askja and Drekagil are close; Herdubreid stands to the north.