Bonifacio

The citadel overhangs the sea on limestone the waves have undercut until the houses lean out further than the cliff beneath them. Bonifacio sits on French Corsica's southern tip, a walled town on a white promontory with Sardinia visible a dozen kilometres away across the strait, while the harbour is a narrow inlet between the cliffs — sailing in feels like threading a needle between fortress walls.

The medieval citadel of Bonifacio is perched on alabaster cliffs on the tip of a narrow limestone peninsula, its tall Genoese houses — the town was Genoa's for centuries — opening onto lanes barely wide enough for two to pass, and the guided visits of the upper town take you through five hundred years of siege and trade. The Escalier du Roi d'Aragon drops from the citadel to the water down 187 steps cut into the cliff face, said to have been carved in a single night during a fifteenth-century siege; the truth is slower and the descent is the same vertigo either way. Below, the harbour fills a fjord-like calanque running deep into the rock, from which boats leave for the sea caves and the foot of the cliffs, where the scale of the overhang becomes clear. The strait beyond is a marine reserve with strong currents, and at dusk the lit ramparts and lanes of the upper town become a Mediterranean stage set.