Hveradalir

The ground at Hveradalir is still working. Steam rises from vents in the slopes, and mud pools bubble close to the path. The hills are rhyolite, so the colour runs from ochre to rust to pale grey, with snow on the peaks behind them. Boardwalks carry the route over the hottest ground. The walking changes constantly: gravel, bare rock, old snow and wet dirt inside a single loop. The sulphur smell is strong in some pockets and gone a few steps later. Allow more time than the distance suggests. Moving from one viewpoint to the next eats an hour or two without any effort.

• Driving in: the approach is bumpy gravel road and its state depends on the weather. A 4WD is needed.
• Weather: wind, cold and sudden changes are normal here, summer included. Bring a windproof jacket.
• Footing: geothermal moisture keeps parts of the path slippery. Wear hiking boots with grip; poles help.
• No facilities: no toilets, drinking water or information point is mapped within 5 km of the valley.
• Stay on the marked trails and boardwalks: the terrain is fragile and the ground under it is hot.

There is no bus. Visitors drive in, and the last stretch is long, bumpy gravel that calls for a 4WD. The nearest mapped car park sits about 1.5 km from the valley and is free; a second lies about 2 km out. From there you walk. One route in starts at the hotel in Kerlingarfjöll, and the ground underfoot changes from gravel to rock to old snow before the boardwalks begin.

Better: a clear day in summer.

Avoid: low cloud, rain and strong wind.

Colour is the whole point here. In sun the rhyolite reads ochre, rust and grey-green; under cloud it flattens out and the steam is all that is left to look at. Rain also makes the mud and the boardwalks slick. Highland weather turns fast, in summer as well, so treat a good forecast as luck rather than a plan.