The Castillo Palacio de Marcilla is a Gothic-style castle built in the 15th century by Mosén Pierres de Peralta. At first it had a defensive character but when the Marquisate of Falces was instituted it became the residential palace of the Marquises. The gateway to the castle, which houses the drawbridge under which the moat runs, is next to what is considered to be the Homage Tower, one of the four towers that make up the corners of the castle. Inside the fortress there was a large parade ground around which the rooms and rooms were distributed. The palace chapel preserves its 16th century paintings.
Acquired by the Government of Navarra in 1976 and thoroughly restored in the 2008-2012 period, it currently houses the town hall and other municipal bodies.
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.