Pozzol Groppo castle was built in the late 12th century on the site of a Roman watch tower. It was restored in the 16th century by the powerful Malaspina noble family, who owned the castle until 1889.
The imposing building preserves inside a beautiful courtyard with a medieval well and sumptuous rooms with fireplaces, wooden ceilings and fresco decoration, keeping alive the prestige of an illustrious past. Today it is not open to the public.
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.