Aqua regia, literally meaning “King’s water”, is a highly corrosive mixture of acids; it is the only mixture of acids that can dissolve gold.
Hungarian chemist George de Hevesy dissolved the nobel prizes of his peers in aqua regia during the German invasion of Denmark in WWII to prevent Nazis from looting the prizes. He placed the liquid solution of gold and aqua regia in plain sight where it was overlooked. After the war had ended, de Hevesy returned to precipitate the gold out of the mixture. He then returned the gold back to the Nobel Foundation where it was then cast back into its original shape. (img)