Schloss Plon (Plon Castle)

Schloss Plon was built between 1683 and 1697 for Duke Joachim Ernst of Schleswig-Holstein-Plon, replacing an earlier medieval fortress on the same hilltop above the Grosser Ploner See, the largest lake in Schleswig-Holstein. The Baroque palace, with its symmetrical wings and commanding hilltop position, was designed to rival contemporary German princely residences despite the modest size of the Plon duchy, which was absorbed back into the Duchy of Holstein-Gottorf after the ducal line died out in 1761. In the 19th century the palace became a Prussian cadet school and later a residence associated with the German imperial family, including stays by Kaiser Wilhelm II's sons, before serving briefly after 1945 as a British officers' school and then a German state boarding school through the later 20th century. The building's Baroque exterior and hilltop terraces remain largely as built, while interiors were adapted repeatedly for institutional use across three centuries, with fewer original 17th-century furnishings surviving than at ducal palaces that stayed in continuous family use. Restoration since the palace was converted to public and museum use in the 2010s has focused on the state rooms and stair hall, presenting the building's layered history from ducal seat through military academy to modern museum rather than a single restored period. The surrounding palace gardens and lake terraces, redesigned in the 19th century in the English landscape style, are open to walk year-round and offer wide views over the Plon lake district.