Inside the palace walls, you will discover the Envoys' Hall, also known as the Hall of Deputies. Look at the ceiling, and you might feel like someone is watching you. Originally, 194 human heads were carved into the wooden coffered ceiling by the sculptor Sebastian Tauerbach in the 1530s. Today, only 30 survive, but they remain remarkably expressive, representing people from all walks of sixteenth-century life. Beyond the architecture, the castle's greatest treasure is the collection of 137 Flemish tapestries commissioned by King Sigismund the Second Augustus. These Arras tapestries, woven with wool, silk, and silver threads in Brussels, were so precious that they were evacuated to Canada during the Second World War to prevent them from falling into enemy hands. They tell spectacular stories from the Book of Genesis and depict strange, exotic animals that the weavers had likely never seen in person.