A collection of 1500 artworks looted by the Nazis in the 1930s and 1940s has been discovered in the German city of Munich.
The collection including works by Matisse, Picasso and Chagall was found by chance, according to German media.
Customs officers investigated a man who seemed to be moving with amounts of cash between Germany and Switzerland.
Cornelius Gurlitt was suspected of tax evasion, and investigators obtained a search warrant for his home in Munich.
There, they found the cache of artworks which had vanished from sight during the Nazi era.
The reclusive son of an art dealer, Mr Gurlitt had reportedly kept the works in darkened rooms and sold the occasional painting when he needed money.
News magazine Focus said investigators put the value of the works at about €1 billion.
The Nazis categorised almost all modern art as "degenerate". It was banned for being un-German or for being the work of Jewish artists.
Some works were confiscated or destroyed and others were sold to collectors for a low price.
There are international warrants out for at least 200 of the works, Focus reports. The collection is being held in a secure warehouse in Munich for the time being.