Malbork castle was medieval Europe’s largest fortress. Picturesquely situated by the Nogat river, the three-castle complex was, for 150 years, the capital of the Teutonic state. The castle's origins date back to the second half of the 13th century. Beginning in 1309, Malbork was the seat of the grand masters of the Teutonic Order and the capital of one of medieval Europe's most powerful states. With a surface area of some 21 hectares, Malbork Castle is the largest Gothic castle complex in the world and a masterpiece of late-medieval fortification and residential architecture. In 1997 Malbork Castle was designated a UNESCO World Heritage Site.
One of the castle's must-sees is the exhibition of Amber Contexts, looking at the gemstone from a variety of possible angles. Tree resin fossilised millions of years ago, amber reflects the complexity of nature. It can be regarded in a number of contexts, including a natural scientific and artistic one. It can also be looked at from a functional perspective. The Malbork amber collection has earned a reputation as one of the world's best and largest.
http://en.visitmalbork.pl/905,The-biggest-gothic-castle-in-the-world.html