Then & now; Gravensteen Castle, Ghent in 1893, just before large-scale restoration began. The castle was in poor condition because monument preservation was not well-known at the time: until ca 1884, a cotton factory was located in the castle itself, and workers’ houses were built against its walls.

For more about its history, watch the mini documentary.
Also not the donjon which back then still had the factory roof of the cotton factory :O