The Castello Angioino-Aragonese sits at the highest point of Agropoli's old promontory, a compact medieval castle with cylindrical towers and walls that have been rebuilt and reinforced by every power that held the town — Byzantine, Lombard, Angevin, and Aragonese in succession. Entry is free, which means the castle is often surprisingly uncrowded despite the quality of the views.
From the battlements you look south along the Cilento coast toward the headlands that mark the edge of the national park, and north across the bay toward Paestum, where the Greek temples are just visible on clear days. Below the castle walls, the old town's lanes wind through white and ochre houses with laundry lines and cats on windowsills — the genuine article, not a heritage reconstruction. Allow an hour to explore the castle and wander the surrounding streets.