Rammenau Castle was built between 1721 and 1735 by architect Johann Christoph Knöffel for Ernst Ferdinand von Knoch, chamberlain of king Augustus II the Strong. As Knoch went bankrupt with the immense costs of this project, Franz Josef von Hoffmann purchased it in a foreclosure auction in 1744. In 1879 it was sold to the von Posern family, with the last owner, Margarete von Helldorff née von Posern, being expropriated by the communists in 1945.
Today it is owned by the State Palaces, Castles and Gardens of Saxony and open to the public, housing a museum with period furniture.
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.