Blue Lagoon, Iceland. [Photo/IC]

Blue Lagoon geothermal spa is one of the most visited attractions in Iceland. 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 such as psoriasis. The water temperature in the bathing and swimming area of the lagoon averages 37C–39 C (99F–102 F). The Blue Lagoon also operates a research and development facility to help find cures for other skin ailments using the mineral-rich water.