When Nazi Germany invaded Denmark in World War II, the Hungarian chemist George de Hevesy dissolved the Nobel Prize gold medals of Laue and James Franck in aqua regia to prevent the Nazis from discovering them. At the time, it was illegal to take gold out of the country, and if it had been discovered that Laue had done so he could have faced prosecution in Germany. Hevesy placed the resulting solution on a shelf in his laboratory at the Niels Bohr Institute. After the war, he returned to find the solution undisturbed and precipitated the gold out of the acid. The Nobel Society then re-cast the Nobel Prize gold medals, using the original gold.