Malbork Castle built
1270 CE.
Shown on the map at 54.040°, 19.028°.
The Castle of the Teutonic Order in Malbork, commonly known as Malbork Castle (Polish: Zamek w Malborku; German: Ordensburg Marienburg), is a Brick Gothic castle complex located in the town of Malbork, Poland, built in the 13th and significantly expanded in the 14th century. It is the largest castle in the world measured by land area and a UNESCO World Heritage Site. It was constructed by the Teutonic Order, a German Catholic religious order of crusaders, in the form of an Ordensburg fortress and named Marienburg in honour of Mary, mother of Jesus. In 1457, during the Thirteen Years' War, the castle was sold by Bohemian mercenaries to King Casimir IV of Poland in lieu of indemnities. It then served as one of several Polish royal residences and the seat of Polish offices and institutions, interrupted by several years of Swedish occupation, fulfilling this function until the First Partition of Poland in 1772.
Text from the Wikipedia article Malbork Castle, licensed CC BY-SA 4.0.