The Blue Lagoon, or Bláa lónið in Icelandic, is one of the most visited attractions in Iceland.

The geothermal spa is located in a lava field in Grindavík on the Reykjanes Peninsula, southwestern Iceland, approximately 20 km (12 mi) from the Keflavík International Airport and 39 km (24 mi) from Reykjavík.

In 1976, a pool generated from the wastewater of the Svartsengi geothermal power plant that had just been built there. People started bathing in it in 1981 after its purported healing powers spread. Years later, in 1992, the Blue Lagoon company was established and the bathing facility was opened to the public.

The warm waters average 37–39 °C (99–102 °F) and are rich in minerals like silica and sulfur. Bathing in the Blue Lagoon is known to aid people suffering from skin diseases such as psoriasis. The facilities also include a research and development department to help find cures for other skin diseases using the mineral-rich water.

The Blue Lagoon is served by the water output of the geothermal power plant and is renewed every two days. Superheated water is released from the ground near a lava flow, and it is used to run turbines that generate electricity. After passing the turbines, the steam and hot water run through a heat exchanger to produce heat for a municipal water heating system. Then the water is supplied into the lagoon for recreational and medicinal purposes.

The rich mineral content is provided by the underground geological layers and forced up to the surface by the water used by the plant. Because of its mineral concentration, water cannot be recycled and must be disposed of in the nearby landscape. The silicate minerals are the main reason for that water’s cloudy blue shade, and although the water reinfiltrates the ground, the minerals form a deposit on the soil, wich makes it impermeable over time, hence the need for the plant to continuously dig new ponds in the nearby lava field.

No trip to Iceland is complete without a visit to the Blue Lagoon, and if you want to know more, visit the Blue Lagoon’s website.