(L-R) The EU, Turkish and Union Jack flags flutter in the wind ahead of the 60th anniversary of "The Treaty of Rome" near the EU institutions, in Brussels on March 21, 2017. Photo/AFP
In Rome on Saturday, EU leaders are set to endorse a "multispeed" Europe that allows some countries to push ahead with cooperation while others lag behind, but which some call a slow disintegration.
After years of burying their heads in the sand, European leaders have finally acknowledged they face an existential crisis.
New European Parliament chief Antonio Tajani said this week that the "European project has never seemed so far away from the people as it does today".
But what makes today's crises different from those that the organisation formerly known as the European Economic Community faced in its early years?
In the 1960s there was the 'empty chair crisis' when France under General de Gaulle blocked decision making, and de Gaulle's repeated 'non' to Britain joining.
Then the oil crisis in the 1970s and repeated referendums on the treaties all posed major challenges.
Still, Europe managed to emerge triumphant from the Cold War and then rapidly expanded in the early 2000s.
It has also pushed through with major projects like the euro and the Schengen passport-free area -- but increasingly tensions over these big achievements are what is driving the EU apart.
"The crises we face today fundamentally call into question the point of the European project," said Frederic Allemand of Luxembourg University.
"Clearly peace is still the frontispiece, but apart from that, what kind of social and economic model do we want in Europe?"
'Muddling through'
The last decade has in particular brought one setback after another.
Following the 2007-8 financial crisis, growth has remained sluggish and unemployment high. The eurozone debt crisis almost forced Greece out and German-led austerity has caused a legacy of bitterness.
Europe has also failed to halt the carnage in Syria and the conflict in Ukraine, both sources of tension with Russia, while a series of Islamist terror attacks have transformed the security environment.
A wave of 1.4 million asylum seekers in 2015 and 2016, largely sparked by the Syria war, has meanwhile shattered the EU's facade of solidarity as Eastern Europe blamed Germany's open-door policy for the influx.
"Never before have I seen such fragmentation and also such little convergence in our union," European Commission chief Jean-Claude Juncker said last year.
Many in Brussels hope that unity in the face of Brexit negotiations, and clarity after key elections in France and Germany, will help to focus minds by the end of 2017.
But they are already divided over what comes next.
Some want to push ahead with defence, especially amid insecurity over new US President Donald Trump's commitment, or the economy, while others in the former Soviet east want to ease off on integration.
But most will still want to keep the advances that the last 60 years have brought, said Hendrik Vos, a professor at the University of Ghent.
"It is not the most efficient and not the most beautiful way to escape from a swamp -- but you can escape a swamp by muddling through and that's the way the EU operates," he said.
