Seljavallalaug

Seljavallalaug was built in 1923 in a valley under Eyjafjallajokull, dug into the hillside so that one long side is the mountain itself, and it was made for a practical reason: too many Icelanders drowned because farm children never learned to swim, and pools like this were built across the country to fix that. It is 25 metres long, fed by a hot spring, and it was for a time the largest pool in Iceland. It has no staff and no entrance fee. Volunteers clean it once a year, so the water quality depends entirely on where in that cycle you arrive - it is often green with algae.

What you actually see

• A pool cut into the hillside - one wall is the mountain.
• Built in 1923 to teach swimming - part of a national push after drownings.
• Twenty-five metres, spring fed - once the largest in the country.
• No staff, no fee - and one volunteer clean a year.

When to go

June to September; the walk in is unpleasant otherwise. Two hours.

Honest expectations

The water is frequently green and slimy and the changing huts are basic and often filthy. It is lukewarm rather than hot in places. The walk in crosses a stream. Ash from 2010 still washes down this valley. Take everything out that you bring.

Nearby

Skogafoss is east; Seljalandsfoss is west on route 1.