As you approach the UNESCO World Heritage site of Pamukkale from Denizli, a long white smudge along the hills to the north suggests a landslide or opencast mine. Getting closer, this resolves into the edge of a plateau, more than 100m higher than the level of the river valley and absolutely smothered in white travertine terraces. Some are shaped like water lilies, others like shell-bathtubs with stalagmitic feet, with the simplest ones resembling bleached rice-terraces out of an oriental engraving. The Turks have dubbed this geological fairyland Pamukkale, or "Cotton Castle".
The responsibility for this startling natural wonder rests with a spring, saturated with dissolved calcium bicarbonate, bubbling up from the feet of Çal Dağı beyond. As the water surges over the edge of the plateau and cools, carbon dioxide is given off and calcium carbonate precipitated as hard chalk (travertine). What you see now has been accumulating for millennia, as slowly but surely the solidified waterfall advances southwest. Seen at sunset, subtle hues of ochre, purple and pink are reflected in the water, replacing the dazzling white of midday. The spring itself emerges in what once was the centre of the ancient city of Hierapolis, whose ruins would merit a stop even if they weren't coupled with the natural phenomenon of the terraces.
Pamukkale Köyü, a once-sleepy village at the base of the cliff, is where most foreign travellers stay. In recent years, the village has acquired a rash of discos, carpet shops, hustlers and wretched restaurants in its centre. Despite all this, it's still a rural settlement, partly dependent on cotton; beyond the main drag, especially in the lower neighbourhood away from the travertine, little outward change is evident. For any nocturnal peace, it's better to stay on the outskirts, whose limit seems to have stabilized about 500m west of the road leading up to the south gate of the ruins.
Most travellers arrive from the agricultural town of Denizli, 20km to the south, from where dolmues labelled "Pamukkale/Karahayat" set off from a rank on the west edge of the otogar; the last departure in either direction is around 11pm in summer (9pm for Karahayat), much earlier in the cooler months. A taxifrom Denizli will set you back 15YTL per car-load; or consider ringing one of the recommended pansiyons, who are often able to fetch you for free (or at least for a reasonable charge).
There are also long-distance bus connections between Pamukkale Köyü and most of the larger resorts – Ka, Marmaris, Kuadası and Fethiye, among other places – up to several times daily, although the buses are really minibuses and not air-conditioned. Several bus companies, including Pamukkale, have ticket offices in the village, but be sure that the fare and itinerary include a shuttle to the Denizli otogar (you'll rarely get through-service, except perhaps in peak season).