Dimmuborgir

Dimmuborgir formed when lava pooled over wet ground here around two thousand years ago: steam rising through the molten rock built chimneys of cooled lava around each vent, and when the pool eventually drained towards the lake, those chimneys were left standing as hollow pillars, arches and walls. Nothing quite like it exists on land elsewhere, though comparable structures are known on the sea floor. Several marked loops of different lengths run through it, the shortest about half an hour, and the large arch at Kirkjan is the usual turning point. In Icelandic folklore this is home to the Yule Lads and their mother Gryla, which is worked hard at Christmas.

What you actually see

• Hollow pillars and arches - lava chimneys left when the pool drained.
• The Kirkjan arch - the set piece on the short loop.
• A formation with few parallels - rare on land, better known from the sea floor.
• Yule Lad folklore - the tradition placing them here.

When to go

May to September for full access; short loops stay open in winter. Two hours.

Honest expectations

Straying off the paths damages the formations and is prohibited. The site takes coach groups through the middle of the day. Paths are gravel with steps and are icy in winter. Facilities are a car park and a seasonal cafe.

Nearby

Hverfjall is minutes south; Grjotagja and Myvatn are close by.