After the eruption of Vesuvius and the silting up of the port of Ostia, and in order to cope with a booming economy, Trajan wanted to strengthen the port supply system in Rome with a system of more modern and larger ports such as Portus and what became the nucleus of Civitavecchia.
The centre probably already existed in Etruscan and earlier times, but it was only with the Optimus Princeps that it experienced a monumental structure, as can still be seen in the remains of the ancient Darsena (dock ) and the Molo del Lazzaretto, complex structures that were the result of the most sophisticated building and nautical engineering of the time.
The visit to the ancient city can also be traced in the organisation of the urban fabric, which has at its centre the square of theancient Forum, the intersection of the Decumanus Maximus and Cardo Maximus (today's Corso Marconi) and the remains of the ancient Aqueduct.
The most important materials from the settlement and its surroundings are preserved in the local National Archaeological Museum.
A short distance from the city centre, the Taurine Baths in an excellent state of preservation still retain their impressive architectural features with the division into specialised rooms by function and the rich decoration that made the 'great Roman baths' famous.
The sulphur springs still in use at Ficoncella are still used for ablutions and therapeutic treatments.