Pamukkale, meaning "cotton castle" in Turkish, is a natural wonder famous not only for the entrancing beauty of its unique geological formations but also for its historical remains. The calcium oxide-rich waters flowing down the southern slope of Caldag located north of the ruins have, over the millennia, built up deposits of white travertine on the plateau thus the name of this place. It is a UNESCO World Heritage Site. The site's ancient name was Hierapolis (Holy City) and it has been a luxury resort town richly adorned with magnificent sculptures. The well preserved theater of Hierapolis offers magnificent view of the plain below. The ancient city of Hierapolis was built on top of the white "castle" which is in total about 2700 meters long and 160m high and can be seen from a great distance.