My favorite astrophysicist and I loved this great story from Richard Rhodes' The Making of the Atomic Bomb, which I found on kottke.org over the weekend:
Exporting gold from Denmark was "nearly a capital offense" under the Nazi occupation of 1940 on. Entrusted with the gold Nobel prize medals of Max von Laue and James Franck (two German Jewish physicists who had fled first to Copenhagen), George de Hevesy and Niels Bohr dissolved the medals in acid to avoid their confiscation (and any complications that would arise from sheltering Jewish refugees). The resulting solution, known as aqua regia, remained undetected in the Niels Bohr Institute and was delivered to the Swedish Academy in 1950 so that they could be recast. [A search for primary source material turned up this page on the Nobel site, which (unromantically and unfortunately) says the Academy decided to recreate the medals with new gold, not the carefully saved original metal. Still, it's a great story.]
