Malbork Castle, also known as the Castle of the Teutonic Order in Malbork, is a medieval fortress located in the town of Malbork, Poland. It was built in the 13th century by the Teutonic Knights, a German Roman Catholic religious order, and served as the headquarters of the order and as a center of their power.

The castle is one of the largest brick structures in the world, covering an area of 143,591 square feet and featuring three main parts: the High Castle, Middle Castle, and Lower Castle. The castle also includes numerous towers, gates, and defensive walls, making it one of the most impressive examples of medieval military architecture.

In 1997, Malbork Castle was added to the UNESCO World Heritage List and has since become a popular tourist attraction, attracting thousands of visitors each year. Today, the castle is open to visitors and features museums and exhibitions that showcase the history of the Teutonic Knights and the castle itself. Visitors can also tour the castle's various rooms, including the chapel, refectory, and the Grand Master's Palace, as well as walk along the defensive walls and towers to enjoy panoramic views of the surrounding area.