The Ahrensburg village came into the possession of the Cistercian Reinfeld Abbey in 1327. After the dissolution of the monasteries due to the Reformation, the whole area came into the possession of the king of Denmark. He rewarded his general Daniel Rantzau 1567 with lordship over these villages. His brother and heir Peter Rantzau built a Renaissance residence in the form of a water castle, now the symbol of the town, and the castle church around 1595. The new schloss buildings were made with parts of the torn-down mansion, on a rectangular island surrounded by a defensive moat. The following year, the chapel was completed. It was modelled on Schloss Glücksburg, built a few years earlier. Four octagonal towers were added later with copper-covered torn heads and lanterns.
The Rantzaus' estate was heavily indebted by the middle of the 18th century and, in 1759, was acquired by the businessman Heinrich Carl von Schimmelmann. Schimmelmann remodelled the castle and village in the baroque style and the current layout of the town reflects these plans.
Historians in Germany consider the building one of Schleswig-Holstein's best-known Renaissance buildings and attractions. Open to the public, it is surrounded by an English park, a chapel, a watermill and a museum.
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.