The Castello di Poggiolo is the most substantial surviving feudal structure in Casanova Lerrone, dating from the medieval period with 17th-century decorative additions. It is privately owned and not open to the public, but visible from the village lanes and worth a walk around for the views and the architecture. The castle changed hands repeatedly between the Del Carretto, Clavesana, and Doria families during the centuries of Genoese control.
The ruins of other feudal structures — the Del Carretto and Maremo castles — are scattered through the surrounding hills. The walk between them through olive groves and maquis takes a couple of hours and provides the kind of slow, meditative hiking that this corner of Liguria does well.