Ussel stands on a rocky shelf above Châtillon, in the middle Aosta Valley, and its form marks a shift in the history of alpine fortification. Instead of a walled enclosure with buildings scattered inside, it presents a single compact block — a rectangular mass with corner towers, windows cut into thick walls, the residence and the defence combined in one volume. It belonged to the sphere of the Challant, the great feudal family of the valley, and later passed through centuries of abandonment, standing roofless above the vineyards and chestnut woods. Restoration has consolidated the structure and made it accessible, and its rooms now serve for exhibitions. Filmed in 4K, with aerial views that make the plan legible, the programme reads Ussel as a piece of architecture: how a fortified house was organised, lit and defended, and what its silhouette still says about power in a medieval alpine valley.
