The exact construction period of Rõngu vassal fortress is not known, but it was probably completed around 1340. The Holy Cross Chapel, located here, was mentioned in the year 1413. During the Middle Ages, the stronghold belonged to the Tödwen family. The fortress was destroyed by the troops of the Order in 1558 and burnt by Jesuits in 1625.
The majority of the castle's layout is not visible over the ground surface. An approximately 25-metre-long section from the outer wall of the eastern side has been preserved, there is also the opening of the main gate. The ruins have not been conserved and fall down gradually. The castle hill is surrounded by a 12-hectare park, which has beautiful majestic oaks, larches and other ancient trees.
Reference: Võrtsjärv Travel Guide
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.