The Blue Lagoon spa is one of the most visited attractions in Iceland. The steamy waters are part of a lava formation. The warm waters are rich in minerals like silica and sulfur and bathing in the Blue Lagoon is reputed to help some people suffering from skin diseases. The water temperature in the bathing and swimming area of the lagoon averages 40 °C (104 °F).
The lagoon is fed by the water output of a nearby geothermal power plant. 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.
It is situated approximately 13 km from the Keflavík International Airport and 39 km from the capital city of Reykjavík. The Blue Lagoon spa and geothermal complex is clearly visible from any of the usual satellite imagery sources at coordinates (63.879, -22.434).
Iceland has a strict code of hygiene and guests are required to shower in the communal shower area before and after bathing.
It is claimed that in June 2007 the Blue Lagoon appeared green, It bewildered the people of Iceland and its tourists.
The Blue Lagoon was used for the thermal spa scenes in the filming of Hostel: Part II. See How to get there.