Malbork Castle (Polish: Zamek w Malborku) is a medieval castle of the Teutonic Order, built in the 13th century, on the Nogat, an estuary of the Vistula River. It is located on the outskirts of the present-day Polish city of Malbork (German: Marienburg) in the Vistula Delta.
From 1309 to 1454, the castle was the seat of the Grand Masters of the Order in the Teutonic Order State. After that, with brief interruptions from 1457 to 1772, it belonged to the Royal Prussian Province, an autonomous Prussian province that opposed the Order and voluntarily placed itself under the patronage of the Polish crown. At times, the castle was also under Swedish control during this period. After the reunification of the Prussian regions as part of the First Partition of Poland, the castle became part of the Kingdom of Prussia in 1772. After World War II, the Soviet occupying forces placed the castle, along with the southern half of East Prussia, under the administration of the People's Republic of Poland.
The extensive complex, with a total area of 21 hectares and a usable area of 14.3 hectares, is considered the largest castle in the world, ahead of Prague Castle on the Hradčany Hill and the Veste Oberhaus near Passau. It is the largest brick building in Europe; with its architectural design in the Brick Gothic style, it became a model for many other buildings, such as the Mürwik Naval Academy. The UNESCO World Heritage Site hosts several exhibitions and can be visited year-round on snow-free days (Wikipedia).