Lake Urmia in northwestern Iran, close to the Turkish border, is the third largest salt lake on earth. Like the better-known Aral Sea, it has been shrinking over the past three decades, its diminishing waters becoming ever more saline. Designated a UNESCO Biosphere Reserve in 1976, most of the lake is an Iranian national park. Yet recent droughts and increased water consumption by local agriculture have lowered the lake's water level, causing salinity to rise to 300 grams per litre -- 8 times that of sea water. In 2011, thousands of people took to the streets of Urmia, the eponymous nearby town, and Tabriz, one of Iran's major cities, calling on the government to take the problem seriously. They fear that Lake Urmia could end up like the Aral Sea, which was deprived of its water sources during Soviet times in a race to cultivate cotton. The Aral Sea's demise is blamed for a catalogue of ecological and health problems among local populations. Some Iranians worry that a similar disaster could befall Urmia. Tabriz, Iran's fourth largest city, sits 100km east, and it’s estimated that some 10 million people could be affected by the lake's demise. Despite the gloom, Iranians are fond of taking mud baths along Urmia's shores and the saline waters are said to be therapeutic for skin conditions, muscle aches and other complaints. Hossein Fatemi explored the lake's surrealist landscapes and met some of the day trippers in search of a free treatment.