Blue Lagoon by HeatherMG Outside the Blue Lagoon, so no people in these pools.
From wikipedia: The lagoon is fed by the water output of the nearby geothermal power plant Svartsengi and is renewed every 2 days. Superheated water is vented from the ground near a lava flow and used to run turbines that generate electricity. After going through the turbines, the steam and hot water passes through a heat exchanger to provide heat for a municipal hot water heating system. Then the water is fed into the lagoon for recreational and medicinal users to bathe in. http://flic.kr/p/9AupvC
Sig Nordal 