Santa María da Armenteira Monastery belongs to the Cistercian order and was founded by the knight Ero de Armenteira in 1168. It has a square cloister, a kitchen, and a tower, all in the 18th-century Baroque style. The monastery was abandoned after the sale of church lands in 1835. The church has a floor plan in the shape of a Latin cross, three naves and three semicircular apses. The central nave is crowned with a pointed barrel vault, and the side naves with groin vaults. The transept has a vault raised on Mudéjar-style pedentives. On the façade, the 12th-century rose window is of particular interest. The whole complex has today been rebuilt thanks to the Association of Friends of the Monastery of Armenteira.
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.