Lost Nazi art discovery: Finding the rightful owners could be impossible. Prosecutors will this morning hold a press conference in Germany to provide more detail about the €1 billion treasure trove of art, lost under the Nazis and found hidden inside a Munich flat. Art historians specialising in returning looted Nazi artwork to their rightful owners have demanded that the German authorities reveal the details of a hugely valuable collection of paintings, discovered in a Munich flat. The remarkable horde of paintings, valued at an estimated €1 billion, was found hidden behind piles of junk in the flat of reclusive 80-year-old Cornelius Gurlitt. They were discovered by chance in spring 2011 when prosecutors began investigating Mr Gurlitt for tax avoidance – but their existence was only made public at the weekend.