Griffen castle was built between 1124 and 1146 by order of Bishop Otto of Bamberg. In an 1160 deed, Emperor Friedrich I mentioned Grivena as a Bamberg property.
In 1292 the Carinthian nobleman Count Ulrich von Heunburg with support of Archbishop Konrad IV of Salzburg occupied the fort in an uprising against Albert of Habsburg, the son of King Rudolph I of Germany and Duke Meinhard II. However Ulrich was abandoned by his allies and one year later had to leave the castle. In 1759 Bishop Adam Friedrich sold the Bamberg estates in Carinthia to Maria Theresa of Austria and the castle was incorporated into the Carinthian duchy.
About 1520 a large reconstruction of the castle took place as a protection against the threat posed by the Ottoman forces with a base amounted of about 4000 m², though the Turks never laid siege to Griffen. In 1659 a flash impact destroyed one of the towers and the decay of the castle began. In 1768 a last religious service took place and about 1840 the roofs were torn. In 2000 the preservation of the castle began. A steep footpath leads up the mountain to the ruins.
Within the mountain is the Griffener Tropfsteinhöhle (dripstone cave) with a length of 485m, which was not discovered until the late days of World War II. It is open to public and a natural landmark since 1957.
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.