Terracina is the point where the Via Appia, the queen of roads, meets the sea after its long straight run from Rome across the Pontine plain. The Romans built the road in 312 BC under the censor Appius Claudius, and for its time it was a marvel: paved, drained and as straight as engineering allowed, linking Rome to Capua and later to Brindisi. The stretch through the Pontine marshes was notorious for mosquitoes and malaria, and travellers often took a canal boat alongside the road instead, as the poet Horace describes in one of his satires.
Here the road hit an obstacle: the Monte Sant'Angelo, whose spur, the Pisco Montano, dropped straight into the sea. In the early second century the emperor Trajan had his engineers cut through the rock to carry the road along the shore, removing a vertical wall of limestone some thirty-six metres high. The cut is still there, with Roman numerals carved into it at intervals marking the depth, and you can stand beside it and marvel. High above town, on the mountain, the ruins of the Temple of Jupiter Anxur look out over the coast with a view that stretches to Circeo and the islands.
The Pontine plain itself was drained and settled under Mussolini in the 1930s, and the new towns built then, Latina, Sabaudia and Pontinia, have a distinctive rationalist architecture. The Appia's modern successor, the SS7, still runs dead straight for tens of kilometres across the plain, lined with eucalyptus and pine trees; it is fast, monotonous and full of lorries, but there is something haunting about following a route that is over two thousand years old.
Terracina, a lively seaside town of thirty thousand people, has everything: fuel stations, beaches, a fish market and restaurants serving clams and fresh seafood. The coast road west towards Sabaudia and Monte Circeo, with dunes on one side and lagoons on the other, is a pleasant ride, while the hills inland towards Sonnino and the Monti Ausoni have tight, quiet roads with lovely views. Summer weekends bring heavy beach traffic from Rome, so plan accordingly.