Henneburg Castle lies on a hill on the right bank of the Main River in the town of Stadtprozelten. Schenken von Klingenberg family built it as a border fortification around 1200. It was the residence of the Teutonic Order for almost 200 years and last served as the official residence of the noble Mainz Amtskeller officials.
It was deserted in the 16th century andfell into disrepair over time. The castle grounds are broken down into the upper castle, consisting of a fortification and main castle, as well as the outdoor grounds with moat and rampart and the defensive wall on the Main river side. The fortifications surrounding the upper castle, several castle gates, seven wall towers or their remains, both Great Hall ruins, the large and small keep and the roughly 150 metre long underground wall-walk accessible through exits in the wall towers, which links the south-west gateway to the northern part of the castle remain intact.
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.