Some decades ago, Lake Urmia in northwestern Iran used to be the biggest salt lake in the Middle East, and the sixth largest lake on Earth. It was once a popular tourist destination, its shores bustled with restaurants and hotels. Vacationers bathed in the saline waters, smearing their bodies with the black mud that purportedly aided ailments from stiff joints to skin afflictions.
The United Nations Environment Program reported in 2012 that 65 percent of the decline came from climate change, while 25 percent was due to dams and another 10 percent from a decrease in precipitation.
 The Guardian: Lake Urmia: how Iran’s most famous lake is disappearing – January 2015
 United Nations Environment Program: The drying of Iran's Lake Urmia and its environmental consequences – 2012. See here.