Marchione castle was a hunting lodge of the Acquaviva of Aragona, counts of Conversano, from around the year 1000 AD. The sumptuous building, with a rectangular shape and four cylindrical keeps on the corner, has been built on three floors. The ground floor, the mezzanine and the four towers date back to the Middle Ages, while the upper floor dates back to the Neoclassic- Baroque age, maybe a work by the school of Vanvitelli.
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.