Siesikai Castle is the residential castle built by Gabrielius Daumantas-Siesickis in the 16th century in the Renaissance style. His heirs were known as Daumantai, also called Siesicki, had given their family name to the nearby town. The masonry palace was reconstructed in the Neoclassical style after 1820 by Dominik Dowgiałło. Only 2 towers remain from the former castle, which had four of them in every corner of the palace. The castle has been undergoing restoration since 1990.
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.