Larciano boasts a castle that dates to the 1300s, with towers at strategic points along the walls. Little of those towers remain today, apart from the 36-metre-high bridge house. Inside the stronghold, visitors can see the old cistern, which gathered rainwater, as well as the foundations of the former house of the captain of the guard. Today it houses the Civic Museum.
The origins of the smaller Castello di Cecina, a tiny hamlet near Larciano, lie in the fourteenth century, whereas in Castelmartini we find the Renaissance-style Villa Poggi Banchieri, nestled in beautiful gardens.