The cotton-castle hillside of Pamukkale is one of Turkey's most photographed landscapes — a steep slope of brilliant white terraces, filled with shallow pools of warm mineral water, dropping nearly 200 metres from the plateau above. The springs feed pool after pool down the cliff, and the calcium carbonate they carry has built the whole formation up over thousands of years. The effect is otherworldly; up close it can look like a glacier, an iced cake, or melted candle wax depending on the light.
On top of the cliff sit the substantial ruins of Hierapolis, a Roman spa town that grew up to make use of the same hot water. You enter the World Heritage site from below or from the upper plateau and the ticket covers both the terraces and the ancient city. Wear something you can swim in if you want to use the thermal pool at the centre, where you can paddle among submerged Roman columns.
The site is about 20 km north of Denizli and reached by frequent dolmuş from the otogar. Try to arrive early or stay through sunset: midday in summer is blinding and very crowded with tour buses.