Building with recycled material may sound modern today, but it was already a good idea 400 years ago. Glücksburg Castle, for example, was built from stones, taken from a neighbouring monastery complex of Cistercian monks, raised in the beginning of the 13th century. Today, the moated castle is not only one of the most important Renaissance castles in Northern Europe. The building, which has been open to the public since 1923, has also been preserved as a living museum - with access to the private rooms, as well as several historical exhibits. Its builder, Duke Johann the Younger, also secured a place in castle history with his 23 children. With only six children, another inhabitant of the castle, Christian IX, could not keep up. However, he soon received the unofficial title of "father-in-law of Europe".
