On the eastern edge of the village is Schackenborg, a small castle from the late 17th century that for the past 20 years has been home to Queen Margrethe’s youngest son, Prince Joachim, and his family. In 2014, however, Joachim and his wife, Princess Marie, announced plans to move to Copenhagen with their two small children, so the castle will be handed over to the newly-formed Schackenborg Foundation.
You'll need to make enquiries locally (start with Tønder's tourist office) to find out whether the castle and/or its grounds are open to the public. In previous summers there have been popular guided tours of the castle gardens once or twice a week.
