1 000 000 000 Mark

Mönchengladbach was among hundreds of German municipalities that issued their own emergency currency — Notgeld — during the hyperinflation crisis of 1923, as the Reichsbank's output simply could not keep pace with the collapsing purchasing power of the mark. By the time billion-mark denominations appeared in mid-to-late 1923, notes of this face value were covering transactions that months earlier would have required only hundreds. Municipal issues like this one were legally tolerated but not officially sanctioned, creating a patchwork of local paper that flooded the Rhineland.

The watermark is worth noting — many Notgeld issues at this denomination skipped security features entirely, printing on whatever stock was available.