Pamukkale

Pamukkale — "Cotton Castle" in Turkish — is one of Turkey's most surreal and beautiful natural wonders: a hillside of white travertine terraces formed over millennia by calcium-rich thermal water cascading down the slope and depositing calcium carbonate that has crystallised into a gleaming white landscape of terraced pools, cascades and stalactites visible from many kilometres away. The thermal pools of Pamukkale contain water at 35°C that is rich in calcium and bicarbonates — soaking in the natural pools (now regulated to protect the formations) is an extraordinary experience. The site is a UNESCO World Heritage Site alongside the ancient Roman city of Hierapolis that sits on the plateau above. Hierapolis was a spa city founded in the 2nd century BC, and its ruins — the necropolis (one of the largest ancient cemeteries in the world), the theatre, the Plutonium (a cave believed to be the entrance to the underworld, deadly due to CO2 emissions) and the Antique Pool (where you swim among sunken Roman columns in 35°C water) — are outstanding. The most dramatic view of Pamukkale's white terraces is from below, looking up at the hillside glowing in afternoon light. Cotton-white against the blue Anatolian sky, it is genuinely spectacular. From the plateau above, views extend across the broad Maeander Valley. Denizli is the nearest major city (20km). Combine with a visit to Aphrodisias (100km), one of the finest and least-visited ancient cities in Turkey.