Viljandi Castle built
1224 CE.
Shown on the map at 58.359°, 25.595°.
Viljandi Castle (Estonian: Viljandi ordulinnus, German: Ordensburg Fellin) is 13th Century castle in a Viljandi, Estonia. It was built by the Livonian Order, and construction started in 1224 in place of a former hillfort, which was one of the strongest castles in Livonia. Finally destroyed in the Polish-Swedish wars during the early 17th century, its ruins still stand near the town centre.
Text from the Wikipedia article Viljandi Castle, licensed CC BY-SA 4.0.