European Union (EU)

The European Union emerged from a sequence of European integration agreements going back to the European Coal and Steel Community (1951) and the Treaty of Rome (1957). The 1992 Maastricht Treaty created the EU as we know it. The euro currency was introduced in 1999 (notes and coins in 2002) and is used by 20 EU member states. The EU expanded dramatically after the Cold War to include former Soviet bloc states. EU membership grew from 12 in 1990 to 27 in the 2020s (28 before Britain's 2020 departure).

The EU represents the deepest experiment in voluntary regional integration in history. It has produced a single market with free movement of goods, services, capital, and people; a common currency for most members; common policies on agriculture, environment, and many other matters; and a parliament directly elected by Europeans. The EU has also faced significant strains, including the 2010 sovereign debt crisis (especially in Greece) and the British vote in 2016 to leave (Brexit, completed 2020).