The remains of the Roman aqueduct – one of the best preserved of northern Italy – imposing and well-known, still stand just outside the contemporary residential area, along the Bormida stream and their construction can be dated back, as it is highly likely, to the first imperial times, perhaps even to the Augustan era (early 1st century AD).
Two separate large parts of the original above-ground structure still exist, respectively made up of seven and eight masonry pillars, quadrangular in shape (measuring between 180 and 300 cm on their side, in proportion to the vertical development of the same pillars) that become progressively smaller upwards with a series of regular offsets, with a height of about 15 metres. Diminished arches rest on the pillars (there are only four left) of 3.35 metres radius, above which ran the water pipe itself, which no longer exists. The route of the aqueduct covers a total length of about 12 kilometres, starting from the water catch basin located in the Lagoscuro area (today in the municipal district of Cartosio), through the Erro valley (along the orographic right side of the stream with the same name), Marchiolli region up to the left bank of the Bormida river, with a total difference in height of about 50 metres.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.