Corse · Corse-du-Sud, France

Citadelle de Bonifacio

A city on a knife-edge: Bonifacio's citadel rides seventy metres of sheer white limestone above the strait to Sardinia, its houses overhanging the void. Besieged by Alfonso V of Aragon in 1420 — the rock-cut 'Staircase of the King of Aragon' plunges to the sea — it is the most dramatic fortified site in Corsica.

At a glance

Built: 9th century origins; Genoese works 12th–16th c.
Style: Clifftop citadel
Commissioned by: Genoese Republic, on older foundations
Signature feature: Ramparts and houses overhanging 70 m limestone cliffs
The staircase: 187 rock-cut steps of the 'Escalier du Roi d'Aragon'
The siege: Withstood Alfonso V of Aragon, 1420–21
Position: France's southernmost town, facing Sardinia across the strait
Visiting: Citadel freely accessible