Brynolf Algotsson, Bishop of Skara, laid the foundations for a fortified castle in Läckö in 1298 originally as a fort that consisted of two or three houses surrounded by a wall. After a fire during the 1470s, the fort was expanded by bishop Brynolf Gerlachsson.
After the reformation in 1527, King Gustav Vasa took possession. Field Marshal Jacob Pontusson De la Gardie was granted the property in 1615. Field Marshal de la Gardie embarked on an extensive building spree, including the third floor of the keep. The portal to the main courtyard was added during his period, as were the frescos depicting people and winding plants found in niches, stairwells and the rooms on the third floor. In 1654, Count Magnus Gabriel De la Gardie initiated immense construction projects at Läckö. A fourth floor was built in the main building and a number of artists were hired to decorate the walls and ceilings of the castle.
Läckö Castle is a national monument and has been managed by the National Property Board since 1993.
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.