For anyone with access to the Smithsonian Channel I recommend their documentary about the 1933 double eagle gold coin. Apparently there are still several unaccounted for out there. The one that was sold at auction fetched the highest price ever for any coin. Even though it was strictly legal to own any one was allowed to auction because the US Gov. had once granted it an export license! After which it was the property of Egyptian King Farouk for a number of years.