Gudlaugsbúð Natural Pool

Reykjadalur — Steam Valley — is a geothermally active valley in the municipality of Hveragerdi in southern Iceland, accessible by a 3-kilometre hiking trail through steaming fumaroles, boiling mud pools, and sulfurous volcanic landscapes before reaching the natural thermal river where bathing is possible in oligomineral geothermal water flowing at 38-40 degrees Celsius. The Reykjadalur thermal river is the most easily accessible and most popular wild thermal bathing site in Iceland, requiring no entrance fee and offering a completely natural, unmediated bathing experience in a geothermal stream directly heated by the volcanic system beneath the Hengill volcano. The short hike through the geothermal landscape — passing hissing fumaroles, vivid yellow sulfur deposits, and steaming hot springs beside the trail — is as much a geological education as a physical preparation for the thermal immersion at the river's natural bathing pools.