European Union

 The European Union (EU) is a political and economic union of 28 member states that are located primarily in Europe.

 The Maastricht Treaty established the European Union in 1993 and introduced European citizenship.

 The latest major amendment to the constitutional basis of the EU, the Treaty of Lisbon, came into force in 2009.

 The EU has developed an internal single market through a standardised system of laws that apply in all member states.

 EU policies aim to ensure the free movement of people, goods, services, and capital within the internal market, enact legislation in justice and home affairs, and maintain common policies on trade, agriculture, fisheries, and regional development.

 Within the Schengen Area, passport controls have been abolished.

A monetary union has been established within union but lacks common Fiscal union.

 EU is composed of 28 member states but only 19 EU member states use the euro currency.

 The Lisbon Treaty now contains a clause under Article 50, providing for a member to leave the EU.

 United Kingdom enacted the result of a membership referendum in June 2016 and is currently negotiating its withdrawal.

 The EU as a whole is the largest economy in the world.

 EU has a common foreign and security policy, thus developing a coordinated external relations and defence.

The membership of EU entails a partial delegation of sovereignty to the institutions in return for representation within those institutions, a practice often referred to as "pooling of sovereignty".

 To become a member, a country must meet the Copenhagen criteria, of the European Council which requires 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.

 The four countries that are not EU members have partly committed to EU's economy and regulations - Iceland, Liechtenstein and Norway.

 The European Council gives political direction to the EU.

 Council of European Union acts together with European Parliament as a legislature.

 European Commission is the Executive arm.

 Court of Justice Of European Union ensures uniform application and interpretation of European Law.

 European Central Bank together with national central bank determines monetary policy.