This map appeared originally in Deutsches Volkstum in aller Welt (Berlin, 1938) and purported to document far-flung German descendants—the map alone was perhaps statement enough to many, striking a deep fear thinking about the 20,000,000 Americans alone whose roots could be traced back to the Vaterland. As a terror and influence tactic that cost little money, it must have caused the anti-propaganda folks a good deal of worry. The German/Vaterland (German American Bund, or Deutsch-Amerikanischer Volksbund) movement never really gained much popular ground in the U.S., though there was some significant compliance in business and trade going on at higher levels of industry and banking.
My grandfather was German (in that his ancestors came to Pennsylvania around 1740) and he fought in the battle of the Bulge. I would give anything to know what he thought of being in that place.
Here’s one of the most widely-believed myths about the medieval ages: that most Europeans thought the world was flat. They did not. Almost all medieval scholars believed the world was round. But it makes the “Dark Ages” sound more backwards and ignorant, and since most people today do not know or care much about the time period, the myth persists.