The European Union (EU) is a political and economic community with supranational and intergovernmental features. It is composed of twenty-seven member states primarily located in Europe. In 1957, six European countries formed the European Economic Community (EEC) by the Treaty of Rome. Since then the EU has grown in size through the accession of new member states and has increased its powers by the addition of new policy areas to its remit. In 1993, the Maastricht Treaty established the current legal framework.
The EU created a single market which seeks to guarantee the freedom of movement of people, goods, services and capital between member states. It maintains a common trade policy, agricultural and fisheries policies, and a regional development policy. In 1999 the EU introduced a common currency, the euro, which has been adopted by thirteen member states. It has also developed a role in foreign policy, and in justice and home affairs. Passport control and customs checks between many member states were abolished under the Schengen Agreement.
With almost 500 million citizens the EU generates an estimated 31 % share of the world´s nominal GDP (€11.8 / US$17.3 trillion) in 2007. It represents its members in the WTO and observes at G8 summits and at the UN. Twenty-one EU countries are members of NATO. Important institutions 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.