The unit of currency used in Europe is the euro (€), which was introduced on January 1, 1999, and became physical currency in 2002. It replaced the national currencies of many European nations, providing a unified monetary system for Eurozone countries, which currently includes 19 of the 27 European Union member states. The euro facilitates easier trade and travel among member countries, promotes economic stability, and enhances the integration of European economies. The European Central Bank (ECB) manages the euro, aiming to maintain price stability and support the economic policies of the member states.