Pamukkale

Where it sits. Pamukkale is a white escarpment on the northern side of the Çürüksu valley in Denizli Province, southwestern Turkey, about 18 kilometres north of the city of Denizli and 250 kilometres inland from the Aegean coast at Kuşadası. The formation is roughly 2,700 metres long, up to 600 metres wide and 160 metres high, and is visible from the valley floor as a bright scar on a brown hillside — the name means cotton castle. Above it, on the plateau, lie the ruins of Hierapolis. The two were inscribed together by UNESCO in 1988 as a mixed site, and the pairing is the point: the city exists because of the water, and the water built the terraces.

How the white rock forms. Groundwater circulating through the fractured limestone of a seismically active zone dissolves calcium carbonate and emerges at the top of the ridge at around 35 degrees, saturated with it and with dissolved carbon dioxide. As the water spreads out and cools, the gas escapes and the carbonate precipitates as travertine, building rimmed pools that grow outward and downward at a rate measurable in centimetres per year. Fresh deposits are chalk-white and soft; older ones weather to grey and buff. The system is fragile and finite, and it very nearly went. Through the 1960s to 1980s hotels were built directly on the plateau, drawing thermal water for their own pools and dumping waste onto the terraces, while a road ran across the formation. Following UNESCO listing the hotels were demolished, the road removed, and a rotation system introduced in which water is directed into selected terrace sections on a schedule. Visitors now walk a designated barefoot channel; the rest is off limits, which is why photographs of empty blue pools and photographs of a crowded white ramp can both be honest.

Hierapolis on top. The city was founded by the Attalid kings of Pergamon in the second century BC and passed to Rome in 133 BC. It was rebuilt after the earthquake of 60 AD under Nero, and its remains are extensive. The theatre, largely Severan, held some 12,000 and retains an elaborately carved stage building with reliefs of Apollo and Artemis. The necropolis spreads for two kilometres along the northern road with well over a thousand tombs — tumuli, house-tombs and sarcophagi — making it among the largest cemeteries surviving from the ancient world, a consequence of people coming here to take the waters and not always leaving. The Plutonium, a small grotto beside the Temple of Apollo, was described in antiquity as an entrance to the underworld where animals died and castrated priests survived; excavation from 2013 confirmed a fault emitting concentrated carbon dioxide that pools at ground level at night, which explains both the deaths and the priests' trick of standing tall. The Antique Pool, run commercially, lets swimmers get in among fluted marble columns that fell into the spring in a seventh-century earthquake.

On screen. It is worth being straightforward here: Pamukkale is not a feature-film location and never really has been. The conservation regime makes it effectively impossible — visitors go barefoot, sections are rotated in and out of use, and camera equipment on the travertine is not permitted. What the site does carry is a heavy load of Turkish television, commercials, music videos and documentary work, all shot from the walkways and the plateau. Travellers assembling a filming-locations route through Turkey will find Cappadocia, Istanbul and the southwestern coast far richer; Pamukkale earns its place on a different basis, as one of a handful of large active travertine systems anywhere, alongside Huanglong in China and the Mammoth Hot Springs terraces in Wyoming.

What the visit is actually like. Three entrances serve the site: the south gate, where a road climbs to the plateau and most coaches arrive; the north gate near the necropolis; and the town gate at the bottom, from which the barefoot walk up the travertine takes about 30 minutes. Shoes are carried, the surface is slippery in wet sections and abrasive in dry ones, and the water in the walking channel is ankle-deep. Sunset from the top of the terraces, looking west over the valley, is the reason many people stay in Pamukkale village rather than day-tripping from Denizli.

Getting there and timing. Denizli is reached by train from İzmir in around three and a half hours, by bus from most Turkish cities, and by air at Denizli Çardak, 65 kilometres away; dolmuş minibuses run from Denizli otogar to Pamukkale village every twenty minutes or so. Day tours from Kuşadası, Marmaris and Antalya are long and arrive in the middle of the day. The plateau and the main archaeological area have level gravel paths and are largely navigable by wheelchair; the travertine walk itself is not.