Pamukkale, unique landmark, is known as a fairyland of dazzling white, petrified castles. Thermal spring waters laden with calcareous salts running off the plateau’s edge have created this fantastic formation of stalactites, cataracts and basins. The temperature of the springs is about 35°C. The hot springs have been used since Roman times for their therapeutic powers. Both the thermal center with its motels and thermal pools and the ruins of the ancient city of Hierapolis are situated on the plateau. Another thermal center northwest of Kusadasi, Karahayit is known for its water’s high-iron content.