When Germany invaded Denmark in World War II , the Hungarian chemist George de Hevesy took the Nobel Prize medals of Max von Laue and James Franck to keep them safe . De Hevesy dissolved the medals , which were made of gold , into aqua regia . When Germany invaded Denmark in World War II , the Hungarian chemist George de Hevesy dissolved the gold Nobel Prizes of the German physicists Max von Laue and James Franck in aqua regia to prevent the Nazis from confiscating them .