Where: Reichenbach, Germany
Constructed: 18th Century
Reconstruction: 1873-1876
Most important renovation: 21st Century
Accessible: yes, museum
Important fact:
Used from 1945 to 1990 as a reception center and for housing, the castle slowly began to decay. Restored to its former (19th century) glory in the early 21st century.
It now houses a museum
https://museum-oberlausitz.de/index.php/de/