Brussels' big fear now is the domino effect of other countries seeking their own votes
And so it begins: the painstaking work of reconfiguring the EU's relationship with the UK after it voted to leave the bloc on Thursday. I spent referendum day in two very different parts of England, beginning the day in rural Wiltshire and ending it in London. In Wiltshire, I saw how the Leave campaign's billboards far outnumbered those for Remain. I spoke to a local retired couple who were dressed up and heading to London for an event at the Imperial War Museum. They both voted to leave. Why? The man argued it was the best way to force what he called a real debate on where the EU is going, adding that he didn't think the bloc would allow the UK to leave in the long run.
His wife said she was worried about immigration.
"We are being overwhelmed by them," she complained, yet struggled to explain what she meant by "them".
Another man chipped in, also insisting that a vote to leave would simply provoke a serious conversation about the EU and that somehow, in his view, the UK would not be adversely affected.
All three seemed unaware of how their vote fitted in the bigger picture: the fact that far-right groups across Europe were hoping for a Brexit, the fact that Russia, which is funding those groups in France and elsewhere, was watching the vote with much interest.
In London, a British-Libyan in his early thirties told me how much the pro-Brexit campaign had unsettled him because of the way immigration became the issue that dominated.
He had watched as the Leave campaign triggered racist and xenophobic sentiment in the city in northern England where he had grown up. "It made me feel like a stranger," he said.
In London too, I spoke to others - some of them British, some transplants from other European countries - in their twenties and thirties who were certain the Brexit campaign would fail, even if it was by a narrow margin.
"How could people vote against their own interests?," asked one. "Impossible," said another.
They woke up yesterday morning, realising what they thought impossible had just become reality. A friend shared a George Orwell quote on Facebook: "The insularity of the English, their refusal to take foreigners seriously, is a folly that has to be paid for very heavily from time to time".
Many others shared a graphic showing the deep generational divide in how the vote broke down, one of the many cleavages the result exposed. It noted how the demographic that had voted most to remain in the EU - those aged under 35 - were the ones who would have to live with the result the longest. Hundreds of thousands of young Britons signed up to register online for the vote at the last minute, causing the website to crash and forcing the registration deadline to be extended. In the early stages after voting had closed on Thursday, Ukip leader Nigel Farage, at that point thinking his side had lost, tried to blame that extension. Hours later, he was euphoric.
How the UK balances the dashed hopes of its youth - a globalised generation that has grown up knowing nothing but the EU - with the hard realities of what a Brexit will mean for their future is one of the many challenging questions facing the country amid the political turmoil the vote has unleashed. If the pro-Brexit camp tapped into fears about the uncertainties of our world today, then it has just forced the UK and Europe into a whole new realm of uncertainty.
A major concern in Brussels now is that the UK decision could prompt a domino effect, with voters in other EU member states demanding their own referendum on remaining in the union.
Earlier this year a survey published by French newspaper 'Le Monde' showed that over 50pc of respondents wanted a vote on France's EU membership.
Marine Le Pen, leader of the far-right National Front, which has experienced a surge in support over the past year, called for a vote this week on what she called the "decaying" EU.
"I would vote for Brexit, even if I think France has a thousand more reasons to leave than the UK," she said.
In the Netherlands, far-right politicians have demanded the same and polls show a majority of voters want a referendum, with respondents evenly split on whether the country should stay in the EU or not.
Italy's Five Star political movement - which recently won 10 out of 20 mayoral elections - is also calling for a vote on EU membership.
Already pummelled by a number of challenges, the European Union now finds the very architecture underpinning it under threat.