In the 1930s, the German government, controlled by the Nazi party, began confiscating all the gold they could, especially from Jews. In 1935, it became illegal for any German to accept or retain a Nobel Prize. At the time, a Nobel Prize medal was made of 23-karat gold and weighed 200 grams. They were embossed with the winner's name, and were therefore hard to hide. Max von Laue received the Nobel Prize in physics in 1914. James Franck received the physics prize in 1925. Both scientists sent their medals to fellow physicist and Nobel laureate Niels Bohr in Denmark for safekeeping.
But in 1940, the Nazis invaded Denmark. They approached Bohr's Institute of Physics in Copenhagen. If they found the medals, it would be evidence that would send von Laue and Franck to their deaths. Bohr turned to Hungarian chemist George de Hevesy to make sure the invaders didn't find the medals... with science! Read the story of how the medals were hidden, or more accurately, destroyed, and how they were eventually returned to their rightful owners many years later, at Today I Found Out.