Evaporation ponds are visible at the potash mine in Moab, Utah, USA. The mine produces muriate of potash, a potassium-containing salt that is a major component in fertilisers. The salt is pumped to the surface from underground brines and dried in massive solar ponds that vibrantly extend across the landscape. As the water evaporates over the course of 300 days, the salts crystallise out. The colours that are seen here occur because the water is dyed a deep blue, as darker water absorbs more sunlight and heat, thereby reducing the amount of time it takes for the water to evaporate and the potash to crystallise.