From economic union via the euro to a migration crisis and Brexit, here is a look at 60 years of ups and downs in the European Union.
May 9, 1950: French foreign minister Robert Schuman unveils proposals for an economic union between France and West Germany.
A year later six countries – Belgium, France, West Germany, Italy, Luxembourg and The Netherlands – establish the European Coal and Steel Community (ECSC).
March 25, 1957: The same six sign the Treaty of Rome that establishes the European Economic Community, a common market.
It takes effect a year later, establishing key European institutions: the Council of Ministers, the executive European Commission and the Parliamentary Assembly, which later becomes the European Parliament.
The first parliamentary elections by direct universal suffrage take place in 1979.
January 1, 1973: Britain, Denmark and Ireland join the EEC. They are followed by Greece in 1981, Portugal and Spain in 1986, and Austria, Finland and Sweden in 1995.
February 7, 1992: The Maastricht Treaty is signed, laying the foundation for a single European currency.
January 1993: A single market allowing the free movement of goods, services, people and capital becomes reality.
November 1, 1993: The EEC becomes the European Union.
It is only in March 1995, however, that travellers in some EU member states will be able to travel without showing their passports under the Schengen accord that drops some internal border controls.
January 1, 2002: Euro banknotes and coins go into circulation in 12 countries replacing national currencies such as the deutschmark, franc, lira and peseta.
Britain, Denmark and Sweden, however, decide to keep their national currencies.
May 1, 2004: In the aftermath of the fall of the Berlin Wall in 1989, the EU swells to 25 members, taking in Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia.
Bulgaria and Romania join in 2007, and Croatia becomes the 28th member in 2013.
Storm clouds gather in 2005 as French voters reject a draft European constitution, as proposed in the Treaty of Lisbon. Three days later, Dutch voters do the same.
Shocked European leaders manage to get the treaty ratified in 2009 with provisions designed to improve the functioning of the enlarged EU institutions.
November 2009: Athens reveals a sharp rise in its public deficit, unleashing a financial crisis across the Eurozone.
First Greece, then Ireland, Portugal, Spain and Cyprus seek aid from the EU and the International Monetary Fund, which demand strict fiscal discipline in return.
Several heads of government fall as austerity measures provoke a popular backlash.
Just as it begins to emerge from the financial crisis, Europe is hit by its most serious migration crisis since the end of World War II with the arrival of hundreds of thousands of asylum seekers peaking at around one million in 2015 according to the International Organisation for Migration.
EU leaders fail to work out a joint action plan.
In the biggest blow to the union, Britain on June 23, 2016 votes 52 percent in favour of quitting the EU, putting itself on course to become the first country to quit.
It comes with the bloc weakened by the rise in populism and euroscepticism.
After three years of disagreement and delays over the divorce terms, the deadline for Brexit is pushed back to October 31, 2019.