The Castle can be visited
Oranienbaum Castle

Oranienbaum Palace in Saxony-Anhalt is a Dutch-influenced Baroque complex in Germany. Initially conceived as a summer residence, it evolved into a widow's seat and later into a palace with a unique English-Chinese garden.
History+
The origins of Oranienbaum Palace date back to 1683, when it was built as a summer residence for Princess Henriette Catharina, wife of Prince Johann Georg II of Anhalt-Dessau and born Princess of Orange-Nassau. The Dutch architect Cornelis Ryckwaert initially constructed a palace with cavalier pavilions and laid out a 28-hectare Baroque garden in the Dutch style. After the prince's death in 1693, Oranienbaum was converted into a three-winged palace and served as Henriette Catharina's widow's residence. The interiors were adorned with leather wallpapers, and a summer dining room with Delft tiles was created in the basement. After Henriette Catharina's death in 1708, the palace was only occasionally used until Prince Leopold Friedrich Franz of Anhalt-Dessau showed renewed interest from 1780 onwards.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 51.8000, 12.4036