The European Union (EU) is an economic and political union of 27 member states, located primarily in Europe. It was established by the Treaty of Maastricht on 1 November 1993, upon the foundations of the pre-existing European Economic Community. With almost 500 million citizens, the EU combined generates an estimated 30% share (US$18.4 trillion in 2008) of the nominal gross world product.

The EU has developed a single market through a standardised system of laws which apply in all member states, guaranteeing the freedom of movement of people, goods, services and capital. It maintains common policies on trade, agriculture, fisheries, and regional development. Sixteen member states have adopted a common currency, the euro. It has developed a limited role in foreign policy, having representation at the WTO, G8 summits, and at the UN. Twenty-one EU countries are members of NATO. The EU has developed a role in justice and home affairs, including the abolition of passport controls between many member states which form part of the Schengen Area, which also incorporates some associated European non-EU countries.

The EU operates through a hybrid system of intergovernmentalism and supranationalism. In certain areas it depends upon agreement between the member states. However, it also has supranational bodies, able to make decisions without unanimity between all national governments. Important institutions and bodies of the EU include the European Commission, the European Parliament, the Council of the European Union, the European Council, the European Court of Justice and the European Central Bank. EU citizens elect the Parliament every five years.

The EU traces its origins to the European Coal and Steel Community formed among six countries in 1951 and the Treaty of Rome in 1957. Since then the union has grown in size through the accession of new countries, and new policy areas have been added to the remit of the EU's institutions.

History

main: History of the European Union thumb|left|Robert Schuman proposing the Coal and Steel Community in 1950 After the end of the Second World War, moves towards European integration were seen by many as an escape from the extreme forms of nationalism which had devastated the continent. One such attempt to unite Europeans was the European Coal and Steel Community which, while having the modest aim of centralised control of the previously national coal and steel industries of its member states, was declared to be "a first step in the federation of Europe". The founding members of the Community were Belgium, France, Italy, Luxembourg, the Netherlands and West Germany.

Two additional communities were created in 1957: the European Economic Community (EEC) establishing a customs union and the European Atomic Energy Community (Euratom) for cooperation in developing nuclear energy. In 1967 the Merger Treaty created a single set of institutions for the three communities, which were collectively referred to as the European Communities, although more commonly just as the European Community (EC).