Pamukkale is also known as Cotton Castle and there are 2 things to see: Ancient city of Hierapolis, a World Heritage Site and travertine.
Travertine is a white concretionary form of calcium carbonate, usually hard and semi crystalline. There is snow-white landscape of terraced pools and small waterfalls. It is forbidden walk through the travertines with shoes. Terraced mineral pools give Pamukkale its name: Cotton Castle.
This area attracted people for its old travertine and thermal water that it is believed to be good for health. Ancient City of Hierapolis was established by the Pergamon King Eumenes II. City was the center for health, religious and art.
