Two photo albums showing art looted by the Nazis during World War II are being donated to the US National Archives.
The Nazis catalogued art stolen from their victims
The leather-bound albums contain photos from which Hitler and his curators could choose art for the Fuhrer's art museum in Linz.
They were created by a special unit set up in 1940 to collect works of art from territories under occupation.
A US archivist said the discovery of the albums could help locate looted works of art that remain missing.
Allen Weinstein called the discovery "one of the most significant finds" related to Hitler's premeditated theft of art and other cultural treasures since the Nuremberg trials.
"It is exciting to know that original documents shedding light on this important aspect of World War II are still being located, especially so because of the hundreds of thousands of cultural items stolen from victims of Hitler and the Nazis that are still missing," he said,
The albums were donated to the US institution by Robert Edsel, president of the Monuments Men Foundation for the Preservation of Art.
He donated them after they were found in the attic of the heirs of a US soldier who was stationed in the Berchtesgarden area of Germany at the end of the war in 1945.
Mr Edsel has donated one of the albums and said he will hand over the second at a later date.
He said the "Hitler albums" highlighted the German dictator's attempt to rob Europe and Russia of their greatest cultural treasures.
"Album 8", which Mr Edsel has already donated, showcases about 50 pages of photos of artwork by French artists Hubert Robert and Francois Boucher.
Most works in the album have already been returned to their rightful owners.
However, many thousands of piece of art and cultural items remain missing or unidentified.
The Third Reich's Einsatzstab Reichsleiter Rosenberg (ERR) unit, which created the albums, was set up by Hermann Goering in 1940 and given the task of confiscating "ownerless" Jewish art collections.
ERR records from 1944 show that the organisation seized 21,903 objects of art from 203 collections in France.
The US National Archives already have 39 of the photo albums, discovered at Neuschwanstein in April 1945.
They were used at the Nuremberg trials later that year as evidence of massive Nazi looting.
It was previously believed that the remaining missing albums, out of a collection of nearly 100, had been destroyed near the end of the war.