The EU

The European Union (EU) is an economic and political union of 27 member states which are located primarily in Europe. 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.
Important institutions of the EU include the European Commission, the Council of the European Union, the European Council, the Court of Justice of the European Union, and the European Central Bank. The European Parliament is elected every five years by EU citizens.
The EU has developed a single market through a standardised system of laws which apply in all member states including the abolition of passport controls within the Schengen area. It ensures the free movement of people, goods, services, and capital,
With a combined population of 500 million inhabitants in 2010 the EU generated 28% of the global economy.
The European Union was formally established when the Maastricht Treaty came into force on 1st November 1993, and in 1995 Austria, Sweden, and Finland joined the newly established EU. In 2002, euro notes and coins replaced national currencies in 12 of the member states. Since then, the eurozone has increased to encompass seventeen countries. In 2004, the EU saw its biggest enlargement to date when Malta, Cyprus, Slovenia, Estonia, Latvia, Lithuania, Poland, the Czech Republic, Slovakia, and Hungary joined the Union.
On 1 January 2007, Romania and Bulgaria became the EU's newest members. In the same year Slovenia adopted the euro, followed in 2008 by Cyprus and Malta, by Slovakia in 2009 and by Estonia in 2011.
On 1 December 2009, the Lisbon Treaty entered into force and reformed many aspects of the EU.
The territory of the EU consists of the combined territories of its 27 member states
The EU's member states cover an area of 4,422,773 square kilometres The EU is larger in area than all but six countries, and its highest peak is Mont Blanc in the Graian Alps, 4,810.45 metres above sea level. The lowest point in the EU is Zuidplaspolder in the Netherlands, at −7 m below sea level.
EU experiences most types of climate from Arctic to sub-tropical.
The EU's population is highly urbanised, with some 75% of inhabitants living in urban areas.
The European Union is composed of 27 sovereign Member States: Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Republic of Ireland, Romania, Slovakia, Slovenia, Spain, Sweden, and the United Kingdom.[45] The Union's membership has grown from the original six founding states—Belgium, France, (then-West) Germany, Italy, Luxembourg and the Netherlands—to the present day 27.
Criteria for joining: a stable democracy,that respects human rights and the rule of law; a functioning market economy and the acceptance of the obligations of membership, including EU law.
There are five official candidate countries, Croatia, Iceland, Macedonia, Montenegro and Turkey. Albania, Bosnia and Herzegovina and Serbia are officially recognised as potential candidates. Kosovo is also listed as a potential candidate but the European Commission does not list it as an independent country because not all member states recognise it as an independent country separate from Serbia.
Four Western European countries that are not EU members have partly committed to the EU's economy and regulations: Iceland (a candidate country for EU membership), Liechtenstein and Norway, which are a part of the single market through the European Economic Area, and Switzerland, which has similar ties through bilateral treaties. The relationships of the European microstates, Andorra, Monaco, San Marino and the Vatican include the use of the euro and other areas of cooperation.

1993 – Belgium, France, Germany, Italy, Luxembourg, Netherlands, Portugal, Ireland, Spain, Great Britain, Denmark, Greece,
1995 -  Austria, Sweden, Finland
2004 -  Malta, Cyprus, Slovenia, Estonia, Latvia, Lithuania, Poland, the Czech Republic,     Slovakia, Hungary
2007 – Romania, Bulgaria

1.1.2002 – Euro