Malbork Castle; The Summer Refectory. It is not only beautiful but it has a story to tell. Above the fireplace in this dining area, you can see a cannonball embedded into the wall. It crashed through a window during the 1410 siege led by Polish King Władysław Jagiełło. The Polish king was informed by a spy about a secret meeting being held in the room by the Grand Master, and the king ordered the Polish gunner to aim for the only pillar in the hall in the hope of bringing down the roof on the Grand Master and his Knights.