The ancient Roman town of Turris Libisonis, located at the mouth of the Rio Mannu rivulet, in the centre of the Gulf of Asinara, was the precursor to the current Porto Torres, which is now, like in the past, a fundamental maritime port in the northwestern part of Sardinia. Ever since prehistoric times, the area, between the current railway station and the course of the river, was a privileged place for dwellings and for its river port: in the beginning, there were nuraghi, followed by urban centres. This had been a Roman colony since the 1^st century BC and, of all the estates belonging to the Republic and the Empire, it was the only one inhabited by Roman citizens: it proudly held the name of Iulia, linked to the figure of Julius Cesar or of Augustus.

Under the long Roman dominion, the town underwent several urban renewals: building of the road system, three thermal baths, an aqueduct and the creation of a port where trade relationships with Ostia took place. The colony, between the end of the 2nd and 3rd centuries AD, was second only to Caralis for number of inhabitants, grandeur and maritime traffic. Buildings that will surprise you with their architectural perfection and evocative power are the domus di Orfeo and the Terme di Pallottino thermal baths as well as the central ones, in an area known as Palazzo di Re Barbaro, in which you will find large rooms with baths and elegant mosaics. Between the 3rd and 4th centuries AD, the building activity was intensified: you can admire the evolution of these activities as well as the remains of marble decorations, bas-reliefs and statues. In the archaeological area, you will find the remains of dwellings grouped into blocks and tabernae (workshops). The buildings are delimited by paved roads and are partly incorporated and visible in the Antiquarium Turritano, a museum located in a building within this area, not far from the thermal baths, where artefacts and relics found during the excavations are kept: pottery, funeral urns, inscriptions and mosaics.

Around the ancient town, there are vast necropolises: one to the west, on a shore of the Rio Mannu rivulet and another to south, below the current town, while to the east, on the seafront, including the hypogaeum of Tanca Borgona, there are the funerary complexes of Scogliolungo and San Gavino a mare and the tombs of Balai. The graves range from the early Imperial age to the early Christian period, while there is an almost completely intact Roman bridge over the river with seven elegant arches, making it an exceptional feat of engineering.