0 Euro - Castelo de Marvão

Marvão's hilltop castle, perched near the Spanish border in Alto Alentejo, is the subject of this 2018 souvenir zero-euro note — one of several hundred regional and cultural subjects commissioned through the EuroSouvenir program, which began in France around 2015 before expanding across Europe. Oberthur Fiduciaire printed the series using genuine banknote-grade security features, including a holographic strip and microprinting, making these the only legally produced zero-denomination notes with full ECB-standard production behind them. The legal tender question is deliberately sidestepped: the European Central Bank tolerates the format precisely because no denomination means no monetary obligation.