Seljavallalaug

Seljavallalaug was built in 1923 by local volunteers led by Björn Andrésson to teach swimming in a remote farming community on Iceland's South Coast. The 25 x 10 m pool is built directly against a hillside where a geothermal spring feeds warm water in continuously at one end; temperatures vary seasonally, running warmer in summer and cooler in winter as rain and snowmelt mix in. It was Iceland's largest pool until 1936 and remains free and unstaffed, cleaned by volunteers once a year; it was buried in ash after the 2010 Eyjafjallajökull eruption and cleared again in 2011.