500 000 000 Mark

Düren was one of hundreds of German municipalities that assumed emergency currency functions during the hyperinflation of 1923, but the denomination here reflects the most acute phase — by late summer and autumn of that year, the Reichsmark had collapsed so catastrophically that half a billion marks represented, briefly, a bus fare or a loaf of bread. Local Notgeld at these denominations wasn't a curiosity; it was a necessity, filling a vacuum left by a central banking system that could no longer print and distribute fast enough to meet daily demand.

The Merkelbach reference numbers 31–32 suggest this type was issued as a pair, likely differentiated by date, serial prefix, or a minor printing variation.