A documentary claimed secret tunnels at Buchenwald could contain Nazi gold Buchenwald and its sub camps was used to house thousands of slave labourers Much of the Nazi war machine was sent underground to avoid Allied bombing Treasure hunters have been warned to avoid a former Nazi concentration camp after a documentary claimed Hitler ordered stolen treasure to be buried in tunnels at the site. More than 56,000 people died in Buchenwald and its satellite camps between 1937 and 1945 where the Nazis used slave labour to excavate massive tunnels initially used as giant factories ADVERTISEMENT However, a new documentary claimed that the tunnels were later used to store valuables stolen from many of the six million Jewish people who were murdered in the Holocaust.