The European Union explained in five figures
In 1993 the six joined with Britain, Denmark, Greece, Ireland, Portugal and Spain to establish the European Union.
The EU grew over the years to reach 28 member nations. However Britain is planning its departure, the deadline for its troubled Brexit process set at October 31, 2019.
The bloc's biggest expansion was in 2004 when 10 countries signed up: eight ex-communist nations, including the Czech Republic, Hungary and Poland; and the Mediterranean islands of Cyprus and Malta.
Nineteen today share the euro which replaced national currencies like the Deutschmark, French franc and Italian lira in 1999, with coins and notes coming into circulation in 2002. Britain, Denmark and Sweden chose to remain outside the euro and recent EU entrants are making preparations to join it.
In force since 1993 and considered among its greatest achievements, the EU boasts that its single market is "the biggest trading bloc in the world".
Its whopping gross domestic product of $17.2 trillion (15.2 trillion euros) in 2017 is behind that of the United States' $19.3 trillion but ahead of China's $12.2 trillion.
513 million people
Germany has the most people (82 million) and Malta the least (468,000).
Stretching from the Atlantic Ocean to the Black Sea, and from the Arctic Circle to the Mediterranean, the EU covers 4.3 million km2 (1.6 million square miles).
It is dwarfed by Russia's 17 million km2 and the United States (9.8 million km2), but is larger than India (3.2 million km2).
France is the largest EU country (632,800 km2, including overseas territories) and Malta is the smallest (316 km2).
Twenty-two EU countries have abolished passport controls between them as part of the Schengen zone.
The mix means a potential 552 language combinations at European Parliament sessions, requiring an army of translators.
One per cent contribution to GDP
Its purse for 2014-2020 is 963 billion euros (around $1 trillion). There is concern that Britain's departure will cause a shortfall.
The EU also has tens of thousands of pieces of legislation and legal acts which member states must adopt, ranging from international agreements to environmental standards for beaches, working hours for lorry drivers and standards for fishing nets.
Sources: European Union website, World Bank, AFP.