Lava from Lúdentarborgir and Þrengslaborgir

Dimmuborgir belongs to the Younger Laxá lava, produced by an eruption along the Lúdentarborgir–Þrengslaborgir crater row approximately 2,300 years ago. Lava travelled towards Mývatn and spread across wetlands, shallow water and an already complex volcanic landscape.

The eruption helped create many of the features now associated with the lake. As lava encountered wet ground and water, steam explosions formed pseudocraters around parts of Mývatn. Elsewhere, lava accumulated, moved through enclosed channels and built unusual structures before draining away.

The familiar explanation for Dimmuborgir describes a temporary lava lake. A solid crust formed across its surface while molten lava remained beneath. Heat interacting with water and wet ground generated steam, around which lava solidified into pillars or chimneys. When the remaining liquid lava drained away, the roof broke apart and collapsed, leaving walls, columns and arches standing above the emptied lake.

This model remains useful for understanding why Dimmuborgir consists as much of empty space as solid rock. Its forms are remnants of material that hardened while much of the surrounding lava continued flowing elsewhere.

Dimmuborgir was therefore not created simply by gas bubbles leaving holes in cooling basalt. It formed through sustained movement, accumulation, cooling and drainage within a much larger lava system.

A More Complex Geological Structure

More recent research has shown that the traditional lava-lake explanation may be too simple. Detailed mapping using LiDAR, ground-penetrating radar and field observations has identified at least two overlapping rootless lava shields at Dimmuborgir.

A rootless shield resembles a small shield volcano but does not stand over its own volcanic vent. Instead, it is supplied laterally by lava travelling from an eruption elsewhere. At Dimmuborgir, lava from Lúdentarborgir appears to have arrived through lava tubes and accumulated in separate ponds or raised structures.

Under this interpretation, many of the pillars and walls are remnants of the margins and internal structures of these lava ponds. As molten lava drained away, the hardened edges remained exposed.

The two explanations are not entirely incompatible. Both involve lava accumulating beneath a cooling surface, forming solid structures and then draining away. The newer research reveals that this occurred within a more complicated system than one large, simple lava lake.

The result is exceptionally rare on dry land. Comparable lava structures have been identified on the seabed off Mexico, but few terrestrial places preserve a complex of this kind where it can be explored on foot.

Walking Inside Dimmuborgir

The marked paths begin near the parking area and soon enter the formations. Even the shorter circuit provides a representative experience, passing among lava pillars and walls before returning in approximately half an hour.

This is sufficient for visitors with limited time, but Dimmuborgir rewards a slower visit. Small openings reveal views towards distant mountains, while a few steps in another direction can close the landscape completely. What initially resembles a collection of individual rocks gradually becomes a connected environment of passages, chambers and broken enclosures.

Every marked route offers something worthwhile. The formations change constantly, and quieter paths can be as visually interesting as the best-known landmarks. Visitors should resist treating the walk as a direct journey between named objects.

The longer circuit to Kirkjan is approximately 2.4 kilometres and usually takes around one hour. Anyone with sufficient time and suitable conditions should include it. The path enters more enclosed parts of Dimmuborgir and reaches the site’s most recognisable formation.

Walking times are approximate. Photography, crowded paths, snow, ice or simply stopping to examine the lava can extend the visit considerably.

Kirkjan – The Church

Kirkjan is a high lava chamber with two broad openings and a naturally vaulted interior. Its form resembles a Gothic church, although every surface was created by moving and cooling lava rather than by human construction.

The formation is impressive partly because it can be entered. From outside, Kirkjan appears as another dark mass among many others. Inside, its proportions and curved ceiling become clear, and daylight entering from both ends defines the shape of the chamber.

Kirkjan is the best-known individual feature in Dimmuborgir. Omitting it from a longer visit would mean missing one of the clearest examples of how lava created enclosed architectural forms here.

It should nevertheless be understood as part of the wider landscape. Dimmuborgir would remain remarkable without Kirkjan because its importance lies in the entire system of walls, pillars, openings and spaces—not in one formation alone.

Visitors must stay on the designated path and should never climb on the lava. The formations can be damaged, and rough-looking surfaces do not necessarily provide safe footing.

From Dimmuborgir to Hverfjall and Reykjahlíð

Dimmuborgir can also form part of a longer walk through the volcanic landscape east of Mývatn. Marked routes connect the area with Hverfjall, the large dark tephra crater rising prominently above the lake.

From Hverfjall, walkers can continue towards Reykjahlíð, reaching the village near the shop or extending the walk to the campground. This creates a journey through several very different results of volcanic activity: the enclosed lava formations of Dimmuborgir, the exposed crater slopes of Hverfjall and the inhabited lakeshore around Reykjahlíð.

This should not be confused with the short circuits inside Dimmuborgir. It is a longer point-to-point walk requiring more time, appropriate clothing and a plan for transport at the far end if the visitor does not intend to return on foot.

Conditions on Hverfjall are more exposed than among the lava formations. Wind, snow and poor visibility can make the extended route considerably more demanding than the sheltered sections of Dimmuborgir suggest.

The Yule Lads and Þrettándinn

The thirteen Icelandic Yule Lads belong to a much older tradition than their association with Dimmuborgir. They were once depicted as troublesome and sometimes frightening figures, each recognised by a name describing his particular habit. Over time, they have become gentler Christmas visitors while retaining their individual mischief.

Beginning on 12 December, the Yule Lads visit human homes one at a time. Children place a shoe in the window before going to sleep. Those who have behaved may find sweets in it the following morning, while a potato traditionally awaits those who have not.

The Yule Lads’ identification with Dimmuborgir is comparatively new. It is not their ancient home in the oldest folklore, but the connection has become an accepted and living part of Christmas in the Mývatn region. The dark chambers, passages and strange towers provide such a convincing home for them that the newer tradition has earned its place.

During the weeks before Christmas, the Yule Lads make appearances in Dimmuborgir. Programmes and visiting arrangements can vary, so anyone travelling specifically to meet them should consult current local information.

The wider family should not simply be relocated to Dimmuborgir. Grýla, the Yule Lads’ formidable mother, lives with their father Leppalúði and the Yule Cat in a cave within Hekla. No one knows precisely where that cave is.

The Yule Lads remain through Christmas and leave on Þrettándinn, 6 January—the thirteenth and final night of Christmas. This is a night when Icelandic tradition allows the ordinary and supernatural worlds to meet. Elves, trolls, the Yule Lads, Grýla and human beings emerge to dance and celebrate around bonfires.

The night marks the end of Christmas, but it also looks forward. In the darkness of the Icelandic winter, the celebration welcomes the returning light and the new sun. Dimmuborgir’s place in this tradition may be modern, but traditions do not have to be ancient to become real.

From Folklore to the Lands Beyond the Wall

Dimmuborgir appeared in the third season of Game of Thrones, representing the Wildling camp of Mance Rayder north of the Wall.

The location required little alteration to appear unfamiliar and severe. Its black formations, snow-filled passages and enclosed spaces already resemble the remains of a settlement built in another world.

Like the Yule Lad connection, the production adds a newer cultural association to the landscape. Neither should overwhelm the geological story, but both demonstrate how easily Dimmuborgir can be imagined as something constructed, inhabited or hidden from ordinary life.

Visiting Dimmuborgir

The main entrance and parking area provide access to the marked trail system. Toilets, food and a shop are available in the service area when open, but visitors should check current opening information rather than assume that all facilities operate throughout the year.

A short summer walk through Dimmuborgir is suitable for most visitors. The paths are defined and the gradients on the principal circuits are generally moderate. Conditions can nevertheless change the character of the walk.

Snow transforms the formations and can make Dimmuborgir particularly beautiful, but ice, deep snow and slush may obscure or block paths. An easy summer circuit can become slow or unsafe. Winter visitors should assess the conditions they actually encounter rather than relying on published summer walking times.

Dimmuborgir is protected as a natural monument covering approximately 423 hectares. Visitors are required to follow marked trails. Lava formations must not be climbed on, broken or otherwise disturbed, and camping is prohibited inside the protected area.

Current protected-area regulations also prohibit dogs unless special permission has been obtained. This is unusual enough that visitors travelling with a dog should verify the current rule before arriving rather than assume that ordinary leash access is permitted.

The protection is not merely intended to preserve several famous formations. Leaving the paths can damage vegetation and smaller lava structures that appear insignificant beside the large pillars but form part of the same geological system.

• • Dimmuborgir formed during the eruption that produced the Younger Laxá lava approximately 2,300 years ago.
  • Recent research interprets Dimmuborgir as at least two overlapping rootless lava shields rather than one simple collapsed lava lake.
  • The name Dimmuborgir means “Dark Castles,” reflecting the resemblance of its lava walls and towers to ruined fortifications.
  • Kirkjan, or the Church, is a naturally vaulted lava chamber reached on the longer marked circuit.
  • Comparable lava structures are exceptionally rare on dry land, although examples have been identified on the seabed off Mexico.
  • The Yule Lads’ association with Dimmuborgir is newer than the characters themselves, but has become a living Christmas tradition in the Mývatn region.
  • Dimmuborgir represented Mance Rayder’s Wildling camp north of the Wall in the third season of Game of Thrones.