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:Towering 52 meters above the sea, Bengtskär lighthouse is the tallest one in Scandinavia. The building started in in 1905 after the shipwreck of S/S Helsingfors and was completed in 1906. The lighthouse was designed by architect Florentin Granholm. On December a special petrol lantern, designed and built in Paris, was brought to Bengtskär and installed atop the tower.
German fleet bombarded Bengstkär in the First World War in 1914. Since the Gulf of Finland was heavily mined, it was not until 1919 that the surrounding seas were declared safe for shipping, that the light was lit again.
After the war the military value of Bengtskär increased as part of the defence system of independent Finland. In Second World War (1941) Soviet Union made a suprise attack to island. After a bloody battle, the small Finnish garrison emerged victorious. Intermittent repairs to the facility continued during the post-war period.