Raufarholshellir

Raufarholshellir formed about five thousand years ago in the Leitahraun eruption: the surface of a lava river cooled and crusted while the molten rock beneath kept flowing and eventually drained away, leaving a tube - the standard way lava caves form, and here it runs about one thousand three hundred and sixty metres. It is among the longest and best known in Iceland. For decades it was open to anyone, and the formations suffered accordingly from breakage and graffiti; since 2017 access has been managed, with a raised walkway, lighting and guides, and the closed sections left to recover. Ice formations build near the collapsed roof openings in winter and last into early summer.

What you actually see

• A 1,360-metre lava tube - drained when the molten rock beneath flowed on.
• Collapsed roof openings - daylight shafts down into the tunnel.
• Winter ice formations - built up under the openings, lasting into summer.
• Managed access since 2017 - walkway and guides after years of damage.

When to go

All year. Two hours.

Honest expectations

Visits are guided and ticketed; the free-for-all era is over. It is cold and wet inside and the floor is uneven beyond the walkway on longer tours. Helmets are compulsory. Damage from earlier decades is visible.

Nearby

Thorlakshofn is on the coast; Reykjavik is half an hour north-west.