0 Euro Der Potsdamer Platz

EuroSouvenir notes are legal tender in the technical sense — issued under a European Central Bank exemption that permits commemorative zero-denomination notes — but no one has ever bought a coffee with one. Oberthur Fiduciaire produces them to the same security specifications as circulating euro banknotes, which is precisely the point: the collector is paying for the substrate, not the denomination.

Potsdamer Platz itself has an odd monetary history worth noting. The square was effectively worthless real estate straddling the Berlin Wall for nearly three decades, then became the most expensive development site in 1990s Germany almost overnight after reunification.