The Adriatic coast of Salento divides the town of Castro into two parts.

High up on a promontory is Castro Superiore, with its marvellous 16th-century castle and the 12th-century Cathedral of Maria Santissima Annunziata, while in an inlet of the coast is Castro Marina and the famous Grotta della Zinzulusa: the most interesting sea cave in the Apulia region, confirming human presence since prehistoric times. The Grotta della Zinzulusa is the only Italian site included in the World Range Ecosystem.