In the EU's single market (sometimes also called the 'internal market') people, goods, services and money can move around the EU as freely as they do within a single country – instead of being obstructed by national borders and barriers as they were in the past.
EU citizens can now study, live, shop, work and retire in any EU country. Or we can stay at home and enjoy a vast array of products from all over Europe.
Most households in Europe are free to choose their electricity supplier.
To create this unified market, hundreds of technical, legal and bureaucratic barriers that used to stifle free trade and free movement between the EU's member countries have been abolished, generating 2.77 million extra jobs and growth of 2.1% between 1992 and 2008.
Free to do business across the entire economic bloc, companies have expanded their operations, with the resultant competition both bringing down prices and increasing consumer choice.
Phone calls in Europe cost a fraction of what they did 10 years ago, many airfares have fallen significantly and new routes have opened. Many homes and businesses are now able to choose who supplies them with electricity and gas.
At the same time, the EU works to ensure these greater freedoms don't undermine fairness, consumer protection or environmental sustainability – aided by Europe's various competition and regulatory authorities.
European firms selling in the EU have unrestricted access to nearly 500 million consumers – giving them a solid basis for staying competitive in the world economy. Not to mention the attraction of such a vast unified market for foreign investors.
And economic integration can be a valuable defence against periodic recessions, allowing EU countries to continue trading with one another rather than resorting to narrow protectionist measures that would worsen the crisis.
Skilled professionals can work anywhere in the EU.
Many areas of untapped potential remain, however, in areas where integration is taking longer:
The market in financial services is a special case, where the EU is seeking to build a strong and safe financial sector - whilst avoiding a repeat of the 2009 crisis - by supervising financial institutions, regulating complex financial products and requiring banks to hold more capital.
The Schengen area is a space without internal borders. It currently comprises 26 countries: Norway, Iceland, Switzerland and Lichtenstein and all the EU member countries except the UK, Ireland, Bulgaria, Romania, Cyprus and Croatia.
The Schengen countries no longer carry out border checks at their internal borders but have stepped up controls at their external borders.
To ensure safety within the border-free area, these countries have also increased police cooperation, in particular through hot pursuit and cross-border surveillance. The Schengen Information System allows national border control, customs and police authorities to circulate alerts about wanted or missing people or stolen vehicles and documents.
Updated in November 2014
This publication is part of the 'European Union explained' series