The Jewish prisoner, the treasure hunters and the secret diary

A few years ago, Menachem Kaiser went to Poland to uncover his family history. All he knew was that his grandfather survived the Holocaust but the rest of his relatives were killed. In search of his family’s lost home, Menachem met a group of treasure hunters who led him to a secret diary and the story of the Nazi’s mysterious underground city, Project Riese. Menachem Kaiser’s book is called Plunder: A memoir of family property and stolen Nazi treasure. Presenter: Mobeen Azhar Producer: Maryam Maruf Get in touch: outlook@bbc.com (Photo: One of the underground tunnels in Project Riese. Credit: Janek Skarzynski/AFP via Getty Images)