Herrstein Castle, on the north side of the town settlement, was built in the latter half of the 13th century by the Counts of Sponheim. The upper castle had originally four towers at the ringwall’s corners, three of which are preserved. The former castle chapel has been since the 15th century a parish church. On the site of the bailey so-called Schloss (palatial castle) built in 1742.
Evangelical parish church Schlosskirche is a single-naved building, partly Gothic, partly Baroque. A quire arch and east part of the south wall date possibly from the late 13th century.
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.