http://en.wikipedia.org/wiki/Badab-e_Surt
“Badab-e Surt is a natural wonder located in Mazandaran Province in northern Iran, 95 kilometers south of the city of Sari. The site consist of a range of stepped terraces made of travertine, a sedimentary rock formed over thousands of years by deposition of carbonate minerals dissolved in water flowing from mineral hot springs.
Badab-e Surt’s terraces are caused by two distinct mineral springs with different natural characteristics, located at 1,840 meters above sea level. The first spring contains very salty water that gathers in a small natural pool. Its water is considered to have medicinal properties, especially as a cure for rheumatism and some types of skin diseases and skin conditions. The second spring has a sour taste and is predominately orange.”
