Europe is the world's second-smallest continent in terms of area, although its population of about 710 million is the third largest - after Asia and Africa. Of Europe's 48 countries, Russia is its largest by area and population, while the Vatican City is the smallest.

European Union

In 2008, 27 of Europe's 48 countries, including the UK, now belong to the European Union (EU), which started in 1957 when 6 European countries formed the European Economic Community (EEC). The UK joined in 1973 at the same time as Ireland and Denmark.

In 1999 it introduced a common currency, the Euro, which has been adopted by 13 member states. It has also developed a role in foreign policy, justice and home affairs.

Find out more about what the EU does.

EU Reform Treaty

The EU is in the process of ratifying the EU Reform Treaty - known as the Lisbon Treaty, the place where it was signed - which is designed to reform the European Union following the failure of the proposed European Constitution in 2005.

The new Treaty was signed by European leaders on 13 December 2007. Member states are now in the process of ratifying it, but the 'no' vote in Ireland's referendum on 13 June 2008 means that the Treaty has been stopped in its tracks. All 27 states must vote in favour before it can be introduced. Discussions are now taking place between member states to try to find a solution to the problem.

EU candidate countries

Negotiations to join the EU are also under way with a number of other candidate states, including Turkey, Croatia, and the former Yugoslav Republic of Macedonia.

Before being allowed to join the EU, a state must fulfil certain economic and political conditions. These basically require that a candidate country must enjoy a secular, democratic system of government, together with the corresponding freedoms and institutions, and respect for the rule of law.

Enlargement of the EU is conditional upon the agreement of each existing member state, as well as approval by the European Parliament.

Main EU institutions

There are a number of EU institutions - including the European Commission, European Parliament and the European Court of Justice - which are designed to ensure that:

• the EU has an agreed agenda
• it can pursue its agreed goals efficiently
• it respects the wishes and interests of its member populations

You might also like to visit the Commission's YouTube channel for more information.

Non-EU states

A number of European countries are not EU members but belong to other groupings. The member states of the European Free Trade Association (EFTA) are allowed to participate in the European Economic Area without joining the EU.

Other Western European countries, including Andorra, Monaco, San Marino and the Vactican City aren't members of the EU or EFTA.