50 000 000 000 Mark

Gaggenau's fifty-billion mark note dates from October or November 1923, the absolute apex of Weimar hyperinflation, when municipal and regional authorities across Germany were legally empowered — and practically forced — to print their own emergency currency, known as Notgeld, simply to meet payroll. By that point the Reichsbank could not produce sufficient denominations fast enough to keep pace with daily price collapses.

Gaggenau was a small industrial town in Baden, best known for its metalworks. That a municipality of its size was issuing fifty-billion mark denominations tells you more about the monetary situation of autumn 1923 than any macroeconomic statistic could.