Someone told me not to long ago that it was (and still is) illegal for US citizens to own stamps from Cuba and North Korea, and that formerly it was also a crime to own stamps from Libya.
Is this true or is it a philatelists' 'urban myth'?
I raise this question because during WWII it was illegal for US citizens to possess stamps from all the Scandinavian countries, including, to my great surprise, Sweden, which was of course not a combatant power or even under German occupation.
The Posthorn (Vol. 2 No. 1, 1945) included illustrations of the banned stamps. Here are the Swedish ones (a batch which, by sheer coincidence, includes the stamp I've decided to make my forum avatar):

If you'd like to read the article, this issue of
The Posthorn can be downloaded here free of charge:
http://www.scc-online.org/old/OldAr...me%202-1.pdfThe Posthorn advised collectors not buy these stamps on the philatelic 'black market' and to wait until after the war to acquire these stamps, when supplies would be plentiful!
A study of the black market in Scandinavian stamps during the war would be very interesting indeed!