The euro is the second most widely used currency in the world, after the dollar. Above all, it is one of the most tangible achievements of the European Union. Its history begins in the early 1970s, when the members of the EEC adopted a system that was supposed to limit exchange rates between member countries. The process accelerated in the 1990s and the currency came into effect for all on January 1, 2002. Actors and witnesses of the birth of the euro testify and retrace the history of this currency, between success and disillusionment or hopes and tensions between European states.