500 000 000 Mark

Hamborn was an industrial city in the Ruhr, and its 1923 notgeld issues came directly out of the French and Belgian occupation of the region that began in January of that year. The occupying forces had moved in to enforce reparations payments in kind after Germany defaulted on timber and coal deliveries, and the resulting economic paralysis — combined with Berlin's policy of passive resistance and deliberate money-printing to fund striking workers — drove inflation to its terminal velocity by mid-to-late 1923.

Hamborn merged with Duisburg in 1929 and ceased to exist as an independent municipality, which means this note was issued by a city that no longer exists.