The European Union (EU) is an economic and political union of 27 member states which are located primarily in Europe. The EU traces its origins to the European Coal and Steel Community (ECSC) and the European Economic Community (EEC) formed by six countries in the 1950s. In the intervening years the EU has grown in size by the accession of new member states, and in power by the addition of policy areas to its remit. The Maastricht Treaty established the European Union under its current name in 1993. The last amendment to the constitutional basis of the EU, the Treaty of Lisbon, came into force in 2009.