Imagine you are living in the 1940’s with the terror of the Nazi menace marching towards your home. This was the plight of physicist Niels Bohr in 1940. One of Jewish descent and one socialist, Max von Laue and James Franck had sent their Noble Peace Prize Medals to Bohr’s Institute for Theoretical Physics for safekeeping. As NPR’s Robert Krulwich describes, this act of sending the 23-karat medals to Bohr’s institute was in and of itself an act of defiance against the Nazi regime, an act likely punishable by death. So as the Nazis march towards his institute, Niels Bohr must get rid of two gold medals entrusted to him. Upon the day of the arrival of the Nazis into Copenhagen, Hungarian chemist Georgy de Hevesy suggested dissolving the gold in chemicals. Gold is cherished for its stability thus dissolving gold presented a unique challenge; however there is one “aqua regia,” a combination of three parts hydrochloric acid and one part nitric acid. The gold medals were reduced to nothing more than an orange colored liquid in a flask, which was subsequently ignored by the Nazis in their search for evidence in order to implicate Niels Bohr in any wrong doing. Georgy de Hevesy’s amazing feats do not end here though, as he took the flask and reconstituted the gold therein in 1950. The gold was then sent back to the Noble Foundation and remade into medals for the two original recipients.

[NPR]