Grimburg Castle was built around 1190 by the Archbishops of Trier to serve them as a regional castle. It was the seat of office for almost 40 Hochwald communities and received a town charter in the 14th century. The castle was taken in 1522 by Franz von Sickingen.
In 1978 the castle was woken from a long slumber and partly restored in the following years. The intensive efforts of the “Friends of Grimburg Castle“ have made it possible to give the numerous visitors of today a rough picture of a medieval castle site. Viewing is possible all year round and the admission is free.
The castle complex extends for a length of about 300 meters and a width of around 90 meters. Thus, the Grimburg was, if not the most significant, at least the most spacious among the former Kurtrier state castles. It comprises a outer bailey, a rectangular keep, a hall (palas), and a chapel. The lower church served the residents of the outer bailey for worship, while the upper church, functioning as a gallery with its own entrance, remained reserved for the archbishop and his officials.
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.