Small museum near to the harbour of Roenne. The castle tower next to the museum is free to visit…read moreand the museum itself is available for a resonable price.
There's a huge collection of different stuff, some organized in the main building and some other in an open storage building with not much information. If you're intersted in military history of Bornholm, mainly of the last 100 years, there's lot to discover. We spent more than an hour there what we didn't expect when first seing the small building.
The main drawback is the lack of description other than Danish. There's a small leaflet in English, german and Polish that explains a little bit but all the details are in Danish language only.