The extraordinary staircases of blazing white thermal pools at Pamukkale are made of soft limestone and connected by calcium-filled waters that trickle down a 200-meter (656-foot) cliff overlooking the Plains of Cürüksu near Denizli, south-east of Izmir. The semi-circular pools range in size up to about six meters (19.5 feet) and are filled with water naturally heated to a pleasant 35°C, which has been known for its therapeutic properties since Roman times. The mineral waters are believed to aid high blood pressure, kidney stones, rheumatism and a variety of skin diseases.
The Roman city of Heirapolis grew above the pools and owed its existence entirely to its proximity to Pamukkale; it began life as a spa town in the second century BC and flourished for centuries before falling into ruin. Today the baths complex and temple remains can clearly be seen alongside churches, a theater and a cemetery. Together the ruins and limestone pools form a UNESCO World Heritage site and are visited by thousands every year.