Pamukkale’s terraces are made of travertine, a sedimentary rock deposited by water from the hot springs. The marvellous landscape of Pamukkale has been created by this gradual formation, leaving a cotton like image.
There are hot water springs with temperatures around 35 °C across the hillside. The water that emerges from the spring is transported to the head of the travertine terraces and deposits calcium carbonate. When the water, supersaturated with calcium carbonate, reaches the surface, carbon dioxide degasses from it, and calcium carbonate is deposited. The depositing continues until the carbon dioxide in the water balances the carbon dioxide in the air. Calcium carbonate is deposited by the water and hardens into travertine.
Located just above the travertine terraces are the ruins of the city of Hierapolis. This superb example of a Graeco-Roman thermal installation was established in this commanding location. The Christian monuments of Hierapolis constitute an outstanding example of an early Christian architectural complex. Hierapolis is a UNESCO World Heritage site.