2 000 000 000 Mark

Cologne's municipal government was one of hundreds of German local authorities forced to print their own emergency currency during the hyperinflation of 1923, as the Reichsbank simply could not produce notes fast enough to keep pace with collapsing purchasing power. This 2 Milliarden Mark note was printed locally by Kölner Verlags-Anstalt und Druckerei — the city never had to look far for capacity.

The signature is the reason collectors pay attention to this piece. Konrad Adenauer was Oberbürgermeister of Cologne from 1917 to 1933, two decades before he became West Germany's first Chancellor. His facsimile signature appears on Cologne's Notgeld issues as a matter of administrative routine — though routine is not quite the word for authorizing a two-billion-mark banknote.