Tubular concrete stilts prop up the protruding structure. Underneath, the Lava Spa’s outdoor swimming pool looks out to the surrounding views.  Photo 3 of 7 in One Night in Iceland’s Famous Ion Adventure Hotel

One Night in Iceland’s Famous Ion Adventure Hotel

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The spa’s outdoor swimming sits below the protruding addition propped up by concrete stilts. All of the Ion’s hot water comes from the ground via geothermal springs, and its energy is provided by geothermal power. The hotel also installed a graywater system; after several layers of cleaning, the water is filtered through the surrounding lava to be reused in 50 years.