Sperlonga & the Torre Truglia
An hour and forty north, up the Lazio coast: a Blue Flag white-sand beach split in two by the 16th-century Torre Truglia, the watchtower built against Saracen raids and now standing on its little headland like a punctuation mark. The whitewashed old town climbs the cliff above. The water is shallow and clear for a long way out.
The town itself is worth the visit beyond the sand. Worth the drive once, even with a 2-hour return.