Rauna Castle ruins was the principal residence of the Archbishopric of Riga in which at for certain period each year it was visited the Archbishop with his entourage. The first mention of Rauna Castle date back to 1381, although historians agree that it may have been built here even earlier. 18th century sources mention the castle as being erected in 1262, following a proposal of Albert Suerbeer, Archbishop of Riga. It is noted that the castle was one of the most important centres of the archdiocese.
The biggest reconstructions occurred under the reign of Archbishop Jasper Linde. One of the new towers built was named Garais Kaspars (Tall Jasper), after the archbishop, and a small settlement developed around the castle, which later became the village of Rauna.
The devastation of the castle started in 1556 with attacks by the Livonian Order, which lasted until the end of the Livonian War. The worst damage to the castle occurred from 1657 to 1658, during the Second Northern War between the Polish–Lithuanian Commonwealth and the Swedish Empire. The castle was deserted after that and slowly turned to ruins. In 1683 the king of Sweden ordered the destruction of anything that resembled a fortress around the castle, so all towers were demolished. Today the Rauna Castle ruins are preserved. Many walls and even the bases of the towers remain.
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.