Torre Canai, Sant’ Antioco, Italy

A 1757 watchtower on the wild southern tip of Sant’Antioco, a small island in the southwest of Sardinia. The tower, built to spot Barbary pirate raids, today watches over three quiet little bays — perfect for a picnic with cliffs, turquoise water and not a crowd in sight. Several benches let you sit and enjoy your picnic, and a sandy beach is a five-minute walk below — perfect for cooling off afterwards.