Bagno Vignoni — the steaming square at dawn

Instead of a piazza, Bagno Vignoni has a rectangular basin roughly fifty metres long, built in the sixteenth century over the hot springs the Romans already used. Water comes out at around fifty degrees, so on any cool morning the whole square smokes, and the arcaded loggia and stone houses around it appear and disappear in the drift.

That steam is the picture. It is heaviest when the air is cold and still — from late autumn through early spring, in the half hour before and after sunrise. Backlight is what makes it visible: put your subjects between the camera and the rising sun on the far side of the basin, and the vapour turns to gold behind them. By mid-morning in summer the effect is gone entirely.

Swimming in the main basin is forbidden and enforced; the free hot pools are downhill below the village, at the Parco dei Mulini, where the water runs over old mill terraces. The village is tiny and mostly pedestrian, with parking at the entrance. Everything here is a two-minute walk, which makes it a good pairing with a Vitaleta sunrise on the same morning.