Pamukkale is a white hillside of terraced pools in southwestern Türkiye that hot water is still building. Springs come out of the ground at about 35 degrees, and as they cool down the slope they drop their dissolved lime as fresh white stone. What you see from the plain is only the working edge of it. The travertine slab behind runs some six kilometres, and most of that is grey and dry, with farmland and an ancient city sitting on top. Down on the white face, shoes come off at the gate to protect the crust, so you walk the wet channel barefoot with warm mineral water running over your feet. The stone is rougher underfoot than it looks, and white rock, turquoise pools and sky flatten into a single glare. Only some basins hold water at a time; they are filled and dried in rotation so the crust can harden, so which ones are full shifts through the year. Late in the afternoon the slope turns pink and the pools go gold.
The city on the ridge is Hierapolis, founded by the kings of Pergamon beside these same healing waters. A theatre is cut into the slope with its carved stage building still standing, and a colonnaded street runs through the middle of the ruins. One of the largest ancient cemeteries in Anatolia spreads around the edges, and many of the people in those tombs had come hoping the springs would cure them. Above the street stands the Temple of Apollo, and beside it a cave the Romans called the gate of Pluto, which breathes out carbon dioxide dense enough to kill. Priests led animals in to die in front of the crowd and walked out themselves; a lethal layer of gas still pools inside at night. The last of the water is in the middle of the ruins. The Antique Pool, the one everyone calls Cleopatra's, is where you swim over the columns and Corinthian capitals that slid in when an earthquake brought the temple down in the seventh century.