I wonder how many pieces he looted were unreturned loot from the Napoleonic conquest? Seems like it'd be a perfect topic for an old style History Channel documentary.
"At the zenith of his power, Göring had one of his four personal trains specially redesigned to transport paintings, and, beginning in 1940, went on shopping sprees, loading the outbound carriages with ‘stacks of freshly minted Reichsmarks’, touring Occupied Europe ‘in collecting mode’."
Though not a documentary, the movie "The Train" with Burt Lancaster depicts this kind of thing really well.