`”In Hitler’s Germany it was almost a capital offence to send gold out of the country. Since the names of the laureates were engraved on the medals, their discovery by the invading forces would have had very serious consequences,” explains the Nobel Foundation. Yet, when `the Nazis occupied Bohr’s Institute and searched it very carefully’ they found nothing. [..]
“While the invading forces marched in the streets of Copenhagen, I was busy dissolving von Laue’s and also Franck’s medals,” [Niels Bohr] wrote in `Adventures in Radioisotope Research’, published in 1962.
Dissolving the medals was not easy, he would recount. For, gold is “exceedingly unreactive and difficult to dissolve.” Thus, the solution was, literally, a solution. “The medals quietly waited out the war in a solution of aqua regia.” After the war, the gold was recovered from the solution and the Foundation presented von Laue and Frank with the `recoined’ Nobel medals.’