Of the castle of the marquises of Clavesana, near Capitolo, the ruins remain: a defensive post on a polygonal plan, enclosed within medieval walls, with two lopped-off towers — one round and the other octagonal.
What to see
The two towers are what you make out best, and the difference in shape between them is the detail that repays the visit. The rest is medieval masonry, partly fallen and partly taken apart: the stones of a castle, in the mountains, have always had a second use.
Visiting
The ruins stand near Capitolo, the settlement where the town hall and the parish church of San Martino are. Onzo is a scattered municipality, so it is worth arriving without hurry: there is more than one hamlet and the distances on foot are not negligible.
Our editors' tip
The castle only reads properly once you know the story the village tells about itself: legend has it that the inhabitants, driven beyond patience by their lord Scipione Del Carretto, attacked it by night, put him to flight and sacked the stronghold, pulling part of it down to recover building material. In 1581 Onzo bought its freedom. That little of the walls survives, after a history like that, is no surprise.