Karahnjukar Dam

The dam is a wall of rock fill 193 metres high and 730 metres long, built from 8.5 million cubic metres of material and the largest of its type in Europe. Behind it lies Hálslón, a reservoir 25 kilometres long holding 2.1 cubic kilometres of water from the glacial river Jökulsá á Dal. The power station itself is underground. Water runs 39.7 kilometres down a headrace tunnel, drops a final 420 metres and turns six turbines of 115 MW each, which makes this Iceland's largest power plant at 690 MW. The scheme flooded highland that formed part of one of the largest unspoiled wilderness areas in Europe. The 2006 book Draumalandið and the 2009 documentary Dreamland both attacked the project, and Sigur Rós played at a protest against the dam.

• The power station is underground. It is not a visitor site; the dam wall and the Hálslón reservoir are what there is to see.
• This is a working plant. Landsvirkjun operates the five dams and the Fljótsdalur Power Station, and the power goes to a single customer.
• The site is remote. The dam stands in the highlands of Fljótsdalshérað; Reyðarfjörður, on the coast, is 75 kilometres to the east.
• The last stretch is on foot. The mapped car parks stop short of the dam, so allow for a walk in each direction.

The dam sits in the highlands of eastern Iceland, in Fljótsdalshérað municipality, and is reached by car. Reyðarfjörður, on the coast, lies 75 kilometres to the east. Two paved car parks are mapped near the site, both a little short of the dam itself, so the last part of the approach is done on foot.

Best: July and August, the only stretch when the highland road is reliably open and the reservoir sits at its fullest. Avoid: winter and the shoulder months, when snow blocks the route entirely. Even in high summer, pick a clear, settled day — low cloud swallows the scale of the place and makes the drive harder.