Karahayıt Red Thermal Springs and Spa Town

Five kilometres north of Pamukkale along the foot of the same fault line lies the small spa town of Karahayıt, where the earth produces a striking geological contrast to Pamukkale's snow-white cliffs. Here, the thermal water bubbles out of the ground significantly hotter (around 55°C to 58°C at the source, compared with 35°C at Pamukkale) and loaded with dissolved iron, magnesium, sulphur and calcium oxides. As the water cools on contact with the air, it oxidises and paints its travertine terraces in vivid bands of rust-red, burnt orange, ochre, mossy green and cream, earning the springs their local name, Kırmızı Su ("Red Water").

Visiting the Red Spring Park (Kırmızı Su Parkı)

At the top of Karahayıt town sits a landscaped municipal park built around the main natural springhead and its terraced red-and-orange travertine mound. Unlike Pamukkale, entering the Kırmızı Su park is completely free and takes only twenty to thirty minutes to walk around. Wooden boardwalks and viewing terraces loop around the steaming source pool, and a shallow warm foot-soaking channel runs along the lower edge where locals roll up their trousers to rest tired feet after walking Hierapolis. Around the perimeter of the park, village women sell local pine honey, dried thyme (kekik, a major crop of Denizli's hills), pomegranate sour (nar ekşisi) and hand-woven Buldan cotton cloths.

How to experience the thermal waters and mud baths

If you want a full soak rather than a quick look at the park mound, Karahayıt is the main thermal hotel zone of Denizli province:

• Five-star thermal resorts and spa hotels: large resort properties in Karahayıt pipe the iron-rich red thermal water directly into separate indoor and outdoor mineral pools (cooled to a comfortable 38°C to 41°C), alongside Turkish hammams, peloid thermal mud baths and freshwater swimming pools. Several hotels sell day-pass spa access to non-guests if you call ahead, or you can book a night with half-board dinner and breakfast included; see where to stay in Denizli.
• Traditional thermal pensions and private family baths (banyo): smaller, budget-friendly apart-hotels in the town streets have deep tiled sunken tubs inside each private room where you turn a tap to fill your own bath with fresh red spring water on demand.
• Practical tip: bring an older or dark-coloured swimsuit, as the iron oxide in Kırmızı Su will stain white fabric orange, and remove silver jewellery before entering the water. Take Minibus Route 70 from the Denizli Otogar straight to its final stop in Karahayıt (about 35 minutes from Denizli, or 7 minutes past Pamukkale village).