https://www.azay-le-rideau.fr

Originally, a fortress was built in medieval times. However, the castle of Azay-le-Rideau was built in 1510. Today, it is one of the famous castles of the Loire region and popular by many visitors. 

The castle of Friedrichstein hosts a museum that represents 900 years of history. The castle has been owned by different families, amongst others the princely house of Waldeck and Pyrmont. 

https://www.schloss-arolsen.de

The palace of Arolsen has been the seat of the house of Waldeck and Pyrmont for centuries. Today, the family still resides in the palace. However, the palace welcomes visitors.