During the Second World War all the collections of the Hermitage museum were preserved/conserved and after the termination of the war they were returned to their original locations.
I think that the word "preserve" is fine in the context, but I'm not sure about "conserve". Is it possible? If so, will the meaning slightly change?
'Preserved' seems to be favoured by most people.
You could look at the Similar Threads below, or plough through this longer discussion.