The euro is the monetary unit and currency of the European Union (EU). On January 1, 2002, currency notes and coins began to circulate in member nations as a non-cash monetary unit. Several other nations adopted the currency. The euro is represented by the symbol €. There were 12 members of the European Community (now the European Union) when the Maastricht Treaty (1991) was signed - the United Kingdom, France, Germany, Italy, Ireland, Belgium, Denmark, the Netherlands, Spain, Portugal, Greece, and Luxembourg (EMU). In the treaty, the euro was advocated, and strict conditions were established for conversion to the euro and membership in the EMU.

The euro began as a political and economic project aimed at unifying Europe after decades of fragmentation. The idea gained traction in the late twentieth century as countries looked for a stable shared currency that could simplify trade and strengthen regional cooperation. The Maastricht Treaty in 1992 set the foundation by outlining the rules for joining a monetary union. In 1999, the euro launched as a digital currency used for banking and financial markets, replacing national currencies in stages. Physical notes and coins entered circulation in 2002, making the euro the everyday currency for millions across the eurozone. Its introduction aimed to reduce exchange rate risk, support economic integration, and create a stronger presence in global markets.