Kamianets-Podilskyi is an old town in the Khmelnytskyi oblast of western Ukraine, marooned on a peninsula of rock inside a canyon that the Smotrych river loops almost completely around it, with a fortress plugging the single neck of land in, and it is entered over a stone bridge into the castle and walked along a rim where the limestone walls fall fifty metres to the river. The pale rock the town is built on is the floor of a tropical sea of more than 400 million years ago, and the river cut the loop through it, leaving a natural moat that made the town one of the strongest places in eastern Europe, fought over by Poles, Ottomans and Cossacks; the only road into the fortress runs along a span of 88 metres that the Ottomans rebuilt during the sieges, which is why locals call it the Turkish Bridge, and the Old Castle behind it was ringed by twelve towers, of which seven stand intact, each raised or reinforced by a different century's defenders, one repaired with money sent by Pope Julius II and named by the locals for the Ukrainian outlaw who kept escaping from it. The Ottomans held the town from 1672 to 1699 and left a minaret of 36.5 metres beside the Catholic cathedral, on which the Poles set a gilded Virgin Mary 4.5 metres tall, still standing over the town.
The old town inside the loop is a grid of churches of three faiths, Polish, Armenian and Orthodox, and a market square, and a footpath traces the top of the gorge around it, with paths dropping to the river at the bottom past ruined water mills among the trees. The fortress is the backdrop of a hot-air balloon festival, and from late October the wooded canyon that rings the town turns gold and rust, so the castle stands above a complete circle of colour. Kamianets-Podilskyi is a town a river fenced in, and the castle guards the one gap.