Many thanks to SWLing Post contributor, Bill Patalon, who shares the following QSL card via Twitter:

Cool #hamradio #QSL card from #PearlHarbor in 1940. Sobering to consider what was to come. #ARRL #SWL #dx #radio pic.twitter.com/uBLNWbTOPz

— @PrivateBriefing (@PrivateBrief) December 6, 2016

Thank you, Bill!