At the top of the Montaillou village is all that remains of The Château de Montaillou, the rectangular castle: a ruined tower and evidence of walls and earthworks. The castle was built by the lords of Alion around the end of the 12th century. Occupying a platform roughly 100m long by 30 to 40 m wide, all that now remains are three walls of the ruined keep. Access was controlled by a dry moat cut into bare rock. The courtyard was surrounded by a curtain wall, the base of which is partially conserved. Further dry moats provided defence to the north and east, while to the south the steep slope of the site was sufficient. The plan of the castle was simple: a wall linked to a tower followed the contours of the hill.
In 1226 Bernard d'Alion paid nominal homage to the King of France, but his sympathies still lay with the Cathars. He married Esclarmonde, daughter of Roger IV, Count of Foix in 1236. The witnesses were Cathar parfaits or at least believers. In 1258, Bernard was condemend by the inquisition as a Cathar heretic and burned alive in Perpignan. The castle was taken by his father-in-law and became a frontier fortress, between the County of Foix, the French King's lands and Aragon. The first written mention of the castle is in 1272, in a list of the Count of Foix's fortresses. At the end of the 13th century, the Count doubled the thickness of the walls. The castle survived the Albigensian Crusade but fell into disrepair later.
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.