Pamukkale literally means 'cotton castle' and is one of Turkey's most impressive natural wonders. It is made up of a series of white travertine terraces cascading down a cliff, which are almost 200 metres high. The hard, white mineral deposits, which from a distance resemble snow, are caused by the high mineral content of the natural spring water which runs down the cliff and congregates in warm pools on the terraces. This is such a popular tourist attraction that strict rules had to be established in order to preserve its beauty, which include the fact that visitors may no longer walk on the terraces. Those who want to enjoy the thermal waters, however, can take a dip in the nearby pool, littered with fragments of marble pillars.
It were the thermal waters which lead to the founding of the spa town of Hierapolis at the end of the 2nd century BC by the dynasty of the Attalids, the kings of Pergamon. The remains include the ancient ruins of the baths, temples, the well-preserved theatre, and the largest necropolis or graveyard in Anatolia containing over 1200 tombs.