Nanstein Castle was built around the year 1162 after Holy Roman Emperor Frederick I demanded its construction as additional defense for the Palatinate.
In 1504, German knight Franz von Sickingen, inherited part of the castle after his father's death in the War of the Bavarian Succession, finally acquiring the entire castle in 1518. He immediately began extensive refortification to make the castle suitable for firearms.
Nanstein is well known for an elaborate siege during the Knights' Revolt in 1523 which claimed the life of von Sickingen. The fall of Nanstein was a symbol for the decline of castles in the Palatinate.
In 1542, von Sickingen's sons recovered Nanstein as a fief and started reconstruction of the castle. Reinhard von Sickingen completed the reconstruction in 1595. In 1668, Elector Charles I Louis forced Lotharingian troops from the castle and razed the fortifications.
In the 19th century the first conservation work was done on Nanstein, and this has continued to the present day.
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.