The original castle on the site of current Château de Combourg was built around 1025 by Archbishop Guinguené, who gave it to his illegitimate brother Riwallon. Major alterations were made between the 15th and 19th centuries. The castle consists of four large, powerful buildings of dressed granite, with crenellations and machicolations, enclosing a rectangular courtyard. In each corner of this massive fortress is a round tower, also with crenellations and machicolations, with conical roofs. In 1761, the Chateaubriand family acquired the property and it was the childhood home of François-René de Chateaubriand (1768–1848).
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.