20 ECU - Charlotte BeNeLux

The ECU — European Currency Unit — was never legal tender in Luxembourg or anywhere else, existing solely as a basket currency and accounting unit tied to member-state exchange rates. Luxembourg's participation in ECU commemorative issues during the early 1990s was partly diplomatic signaling ahead of the Maastricht Treaty's monetary union provisions taking effect. Charlotte, Grand Duchess from 1919 to 1964, abdicated in favor of her son Jean and spent her later years as a symbol of wartime continuity — she had broadcast radio addresses from exile in London and Montreal throughout the Nazi occupation.