0 Euro Ville de Luxembourg Spécimen

Euro Souvenir notes occupy an odd corner of the hobby — technically legal tender for zero euros, they're produced under license from the European Central Bank and sold as collectibles at tourist sites across the eurozone. Oberthur Fiduciaire, one of the continent's established security printers, handles the series, which keeps the physical construction close enough to genuine currency to satisfy the licensing terms.

Luxembourg City joined the program in 2019. These sell at point-of-issue for several euros each, which means the markup over face value is, literally, infinite.