There are numerous powerful exhibits at Risiera di San Sabba in Italy, where Jews and political prisoners, amongst others, found themselves.
These are ashes from Auschwitz concentration camp, placed here in 2005 by the National Association of Former Nazi Camp Deportees organisation (ANED). I don’t know the back story to this of when they were collected, but I imagine that this was shortly after the end of the Second World War. Their symbolic meaning is what is powerful though, there were around 6,000 Jews in Trieste in 1938, with around 1,500 left after the Second World War whilst today, there are around 600 members of the Jewish community in the city.