Parco Nazionale del Circeo

The walls of Circeo's Acropolis were built in local limestone during the Roman Mid-Republic (3rd-2nd century b.C.). The enclosed area - around two hectares along the mountain edge - was roughly square; the walls were built in straight stretches, whose length depended on the shape of the ground.

Today, their height is not uniform; on the north-western side there is the the highest preserved portion (6 metres). There, as in the other sections where walls are still quite high, it can be easily observed how walls are thicker at the base and get thinner toward the top, by about 10 cm per each vertical metre.