Pamukkale, Turkey
Also referred to as the Cotton Castle, this serene landscape looks like it belongs on Venus. Mineral pools surround white, “cotton-like” ridges and shelves. This is all thanks to the high concentration of calcium bicarbonate which spills over the edge of the cliff. You can relax in the myriad of natural spa pools in this otherworldly location. Ruins, temples, and Greek monuments can be found at the site (WHC).