The Via Flacca was a Roman road along the western coast of Latium, Italy.
[4] It was a side branch of the via Appia, the much more famous Roman consular road, which it rejoined after Formiae near the Rialto bridge, and provided an alternative route to avoid the Aurunci mountains.
The areas along the coast of Formiae and Caietae were popular resorts and sites of seaside villas of many important rich patricians of Rome, notably the grandiose villa of the emperor Tiberius at Sperlonga.
Livy says: "Flaccus separately built a dam at the Neptunian spring that the people might have a footpath there, and a road over the hill at Formiae..."[5] At the cliffs at Formia, it passes at an altitude of 30–40 m, and is supported by terraces in double polygonal walls with opus caementicium (concrete) to anchor them to the rock.
At Punta Cetarola, south of Sperlonga, the track is supported by a wall of square and polygonal stone and passes through a natural cave, the Antro di Punta Cetarola, then further north leads to the Torre Capovento.