Arnarker lava cave

Arnarker is a wild lava tube. There is no lighting, no handrail inside and no guide, and nothing marks the way through. A steep staircase drops into the tunnel, and past the entrance it goes fully dark. The passage runs in two directions. The shorter end puts you on hands and knees in places, and it holds stalactites and ice formations. The longer end can be followed to its end, and the further in you go, the more icicles there are. The rock is sharp underfoot and at hand height, which is why gloves are worth packing. The route through is the one you pick yourself.

• Light: Bring a torch or headlamp and a spare. The cave is fully dark and nothing inside is lit.
• Hands and feet: Sturdy footwear and gloves. The rock is sharp, and the shorter end needs crawling.
• The stairs: A steep staircase leads down into the cave. Anyone unsure on rough ground should stop at the top.
• The road sign: A sign reading Lokað (closed) stands on the road in, and in winter that road is icy.
• No supervision: Entry is free, unguided and open around the clock. Tell someone where you are going.

You get here by car, and the two approaches are not equal. Come from the north-east, past the water bottling plant. That way adds around 12 km on paved road and finishes with roughly 1.5 km of reasonable gravel. The south-west approach is 10 km of very rough gravel that can damage a car, at a crawl of about 15 km/h, and GPS routing tends to prefer it because it is shorter. Parking at the cave is free. From there a steep staircase leads down into the lava tube.

Better: the snow-free months, when the access road is clear.

Avoid: winter, when the road in is icy.

Winter is not needed for the ice. The icicles and ice formations sit deep inside the tunnel and are there in the warm months too. Time of day makes no difference underground, since no daylight reaches past the entrance.