50 Céntimos Olvena

Olvena is a village in the province of Huesca, Aragon, that by the late 1930s had a population numbering in the dozens. That a municipal council of this scale was issuing its own fractional paper currency is less surprising than it sounds — the Spanish Civil War's disruption of coin supply forced hundreds of tiny Republican-held municipalities to print their own emergency change notes, a phenomenon so widespread that specialist catalogs like Gari run to thousands of entries covering localities most Spaniards have never heard of.

The official stamp is the sole security feature, which was entirely typical for village-level issues where printing infrastructure was whatever happened to be locally available.