5 000 000 000 Mark

Kandern is a small town in the far southwest of Baden, close to the Swiss and French borders — not the sort of place one expects to find five-billion-mark emergency currency. But by late 1923, municipal authorities across Germany were printing their own Notgeld simply to keep commerce moving, as the Reichsbank's output could not keep pace with hyperinflation that was doubling prices within hours. Fritz Günther's print shop in nearby Lörrach handled the job, which was standard enough for small-town issues of this period.

The official stamp substitutes for more sophisticated security — the entire anti-counterfeiting burden placed on a single ink impression, which tells you everything about how long anyone expected these notes to remain valid.