Monumento Naturale Palude di Torre Flavia

Imperial Villa in Marina di San Nicola
Remains of a building of considerable dimensions, probably belonging to Pompeius, the sworn enemy of Caesar; however, it is certain that during the imperial period the villa belonged to emperors of the Antonini and Severi dynasties.

Odescalchi Castle (it can be visited only outside)
Belonging to the ancient and noble homonymous family, it is a building dating back to the 14th century. Next to the castle, there are the ruins of the ancient Etruscan harbor of Alsium, one of the three landings of Caere, an Etruscan economic power in the 6th century BC, today known with the name of Cerveteri.