Surtshellir

Surtshellir runs for close to two kilometres through the Hallmundarhraun lava field and is one of the longest caves in Iceland. It is named for Surtr, the fire giant of Norse myth, and the medieval sources place outlaws living in it. Excavations at a stone structure inside have found animal bones, beads and other material dating to soon after settlement, which researchers have interpreted as ritual activity rather than simple shelter - the reading is debated but the deposits are real. Inside, the floor is broken blocks the whole way, ice remains in the lower sections into summer, and there is no lighting of any kind.

What you actually see

• A lava tube close to two kilometres long - among the longest in the country.
• A structure inside - excavated finds pointing to early ritual use.
• A name from Norse myth - Surtr, the fire giant, and outlaw traditions.
• Ice underground into summer - in the deeper sections.

When to go

June to September, when the track is passable. Two to three hours.

Honest expectations

The floor is unstable broken rock and ankle injuries are common; helmets and strong torches are essential and a guide is sensible. There is no lighting, no marked route and no signal. The access track is rough. Removing anything from the cave is prohibited.

Nearby

Husafell is east; Hraunfossar and Reykholt are along road 518.