Six thousand feet under Iceland's surface, geothermal activity heats water to 320°F. In the 1970s, the country's leaders sought to find a way to use this water as a central heating source for homes and buildings. But because of the close proximity to the ocean, saline and other minerals from seawater have seeped in, making it unsuitable for direct central heating. In 1976, however, the Suournes Regional Heating Corp. discovered an answer: The geothermal water could be used to heat natural spring water, which can be used for central heating.

After the geothermal water heats the spring water, it is drained in the surrounding lava fields. However, in one area, the lava proved too dense and the water collected to form a warm pool, providing an unanticipated and surprising benefit for Icelanders. High levels of blue-green algae and minerals, such as white silica, formed a light, natural sediment on the pool's bottom, giving the pool a milky blue color. In 1981, one of the power plant's workers, plagued with chronic psoriasis, began soaking in the waters. Within weeks, his condition greatly improved, and word of the "healing lagoon" spread. A few years later, it opened to the public so that everyone could benefit from the skin-conditioning properties of the water.

The Blue Lagoon, open year round, is conveniently located between Keflavík International Airport and Reykjavík, so travelers who have a layover in Iceland can take advantage of these healing waters. In 2000, the Blue Lagoon played host to 318,000 guests, and it is currently slated for development as a spa. The silica mud provides a wonderful exfoliant and leaves the skin soft and refreshed. It is common to see visitors soaking in the warm waters and rubbing the white mud on their skin. The Blue Lagoon also accommodates the Clinic for Natural Treatment of Psoriasis, a facility benefiting people from all over the globe.

From September through May, the Lagoon is open 10 a.m.-8 p.m., Monday-Wednesday, and until 9 p.m. Thursday-Sunday. During the summer, hours are from 9 a.m.-9 p.m. every day. The fee is about $10 for adults, $5 for teens and free for children under 12. Visit www.bluelagoon.is. for more information.