0 Euro - TORRE DOS CLERIGOS - PORTO

The Torre dos Clérigos souvenir series sits in an odd corner of numismatic collecting — zero-denomination notes have no legal tender status anywhere, yet Oberthur Fiduciaire produces them to the same security specifications as circulating currency, hologram included. The EuroSouvenir program was formalized around 2015 and has since expanded aggressively across European tourist sites, with each note tied contractually to a single location and print run.

Oberthur's involvement matters here. The Tours-based firm has printed currency for over 70 countries; applying that infrastructure to a souvenir item is commercially rational but gives these notes a technical authenticity that purely decorative tourist items lack.