At the back of a police station in the Italian capital of Rome is a warehouse that holds one of the most valuable art collections in Europe. Behind the armoured door is a vault that looks like it belongs to a compulsive hoarder. But instead of being filled with trash, it is an Aladdin's cave of treasure.

Works from Picasso, Banksy, Warhol, Modigliani and a $300 million Van Gough are found alongside carefully labelled bronze statues and marble busts. But there is a reason this coveted haul isn't on public display — everything is either stolen or fake. The artefacts have been recovered by the Italian Carabinieri Art Squad.