Koknese Castle (Latvian: Kokneses pils, German: Burg Kokenhusen) is a complex in Koknese, Latvia, dating from the 13th century. The castle was situated on a high bluff overlooking the Daugava river valley. In 1965 a hydroelectric dam was built downriver, creating a reservoir that partially submerged the castle and flooded the surrounding valley.
The ruins are picturesquely surrounded by water and in front of a very beautiful park. Entry costs €2.50 for adults; dogs do not need a ticket.
Built at the beginning of the 13th century by the Bishop of Riga on the south-western border of his diocese on the site of a burnt-down previous structure, Kokenhusen Castle stood on a 30-meter-high rocky outcrop on the Daugava Valley. It was part of a strategic chain of bishop's and order castles along the Daugava, which began with Daugavamünde and extended via Riga, Holme, Uexküll and Lennewarden to Kokenhusen.
Changed and rebuilt many times over the years, the complex was destroyed by explosions at the beginning of the 18th century. Its ruins, which have been listed as a monument since December 16, 1998, have been a popular tourist destination in the region since the end of the 19th century and are now almost completely surrounded by the water of a reservoir for the Pļaviņa hydroelectric power station. (Wikipedia)