Malbork, formally know as Marienburg (Mary's Castle) was built in 1274 and served as the headquarters of the Teutonic Order. It is the world's largest brick Gothic castle and at one point housed up to 3000 Teutonic Knights. It was never conquered by force, but was handed over to the soldiers of Bohemia as a substitute for their mercanary wages. Then in 1457, the mercenaries sold the castle to the King of Poland. Over 50% of the castle was destroyed during WWII, but has been restored since.