The ruins of the city of Portus (the “port” of Rome par excellence) stand at about three kilometres from the present day coastline: the motorway network, the Fiumicino airport infrastructures, and progressive urbanization make it difficult to find it from land, even though the archaeological site is “signposted” by the luxuriant vegetation with its high trees, eucalyptuses, holm-oaks and pine trees, which were originally planted in the Torlonia family parkland at the beginning of the 20th century, after land reclamation. There are still a few remains (mainly the right-hand wharf) belonging to the earlier port of Emperor Claudius, inaugurated by Emperor Nero but soon silted up. The wharf can be seen stretching for about 800 metres along the boundary of the airport. The areas that can be visited belong to the port designed by Trajan and continued by his successors. It was a highly functional port, more suitable to the increasing needs of the Empire’s capital city. Of course, the best hydraulic experts of the time were employed to design and build the port of Rome, proof of which is the fact that the installations are still of an excellent quality. Unlike the earlier 1st century port, which extended out into the sea with two pincer-shaped wharfs, this later port was centred around an internal basin, connected to the sea by the earlier basin. It was also linked to the Tiber river by an artificial canal (Fossa Traiana, now the Fiumicino canal). We do not know the entire extension of the town that grew up around the port down to the first Barbarian invasions; it has been estimated that about 65/70 hectares of land were enclosed in the first defence walled area, dating back to the 4-5th centuries, but population numbers are uncertain. Evidence of the population has so far been found in the remains of very late period housing (7th-8th century) in the north east area, an unusual complex (the so-called Palazzo Imperiale) to the north and warehouses and/or merchant houses, in addition to the port structures. The eastern sector of the area is private: the state owned part, while containing the most important monuments, does not include the large hexagonal basin, the focus of the ancient port.