European museums hold hundreds of thousands of colonial-era artefacts, many of them looted across centuries from their places of origin in Africa, Asia and the Americas.
In recent decades, there has been a heated debate about whether, how and when these objects of huge cultural significance should be given back.
Yet, despite frequent promises from Western governments to consider the matter, only a handful have ever been returned.
Now, activists have begun taking matters into their own hands.
Journalist Allan Clarke has been finding out why.