The white pillars of the Parthenon, which sits at the top of the Acropolis, still stand strong 2,500 years on - a symbolic testament to the enduring idea of a government by and for the people. In the words of the Athenian general Pericles, "a government in the hands of the many, not the few."
This time, President Obama comes to Europe as the defeated champion of two causes lost to democratic votes: opposition both to the election of Donald Trump as President and "Brexit," the British vote to leave the European Union.
For both the US and the EU, these are uncharted waters: how will President-elect Trump -- the only candidate in US history to have won without any experience in government, the law or the military -- deal with Europe, but especially the European Union?
Perhaps nothing spoke to EU fears more clearly than the photograph tweeted by Brexit champion and leader of the UK's anti-EU UK Independence Party (UKIP) Nigel Farage, grinning inside a golden Trump Tower elevator
, getting a thumbs up from the President-elect himself.
Europe is fracturing Trump's victory has only widened the cracks further.
Consider this: France faces a Presidential election in a little more than six months and British betting agency, William Hill, has already recalculated the odds of the far-right candidate Marine Le Pen (once a distant long-shot and the butt of political jokes) becoming the French President: jumping from 8/1 to a much more likely 2/1.
Inspired by Brexit and Trump, Le Pen has made it clear she would hold a referendum to take France out of the EU.
"There is absolutely no reason why the European Union should continue moving forward in this totalitarian way -- at some time we have to stop and ask the question to the people of the various European countries: Do you still agree with all this? Do you agree with what the EU has become?" she told the BBC's Andrew Marr in an interview over the weekend
"I am absolutely convinced that if we did ask the question through a referendum in each country, the elites would be in for another surprise!"
And that's just in France. The Netherlands has Geert Wilders, with his own Trump-sized mane of silver hair and persistent calls for banning Islam from the country. Germany has Frauke Petry, a fresh-faced young female politician whose key demand is to "stop immigration altogether." All three are nationalist, far-right politicians who had seen a surge in the polls even before Trump boosted their odds.
As if the internal populist revolts were not enough, the EU is also seeing fault lines widening north to south on debt issues and east to west on refugees and immigration.
A Europe united by 'national-cultural' identities
Greece and Italy remain deep in debt with no discernible way out, even as the EU's economic giant in the north, Germany, tightens the austerity screws.
In the east, the so-called Visegrad Group of nations -- Poland, Hungary, Slovakia and the Czech Republic -- have formed a strong block against resettling refugees and increased migration, to the weak protests of Germany and France in the west.
Hungary's President, Viktor Orban, envisions a Europe united by "national-cultural" identities, not a common set of liberal European values, as he told the Telegraph newspaper in Britain:
"If we want to survive, this is the only way. To base our future on national-cultural identity. Otherwise we have no chance of surviving as Europe. We are not Europeans because we have 'common European values,' this is a misunderstanding."
He said, "We have to respect the fact that the people would like to have the feeling of that they control their own lives, and that there is no such thing as a 'European nation.' We have French, we have Germans, we have Hungarians but there are no European people. So the legitimacy, the democracy can come only from the nations, nowhere else. So if someone wants to build a European architecture over the European people, that's sad. It's a house built on sand, not on rock."
How will Obama address a divided Europe?
This is the divided Europe that President Obama now seeks to address. He will spoke to the Greek people in Athens on Wednesday, focusing on the challenges of globalization and the interdependence of global markets.
He will also meet with the leaders of Italy, France, Germany and the UK on Friday, in what was supposed to be a farewell state visit, but what is looking increasingly like an emergency briefing on the incoming presidency.
Perhaps his most poignant meeting will be his one-on-one with German Chancellor Angela Merkel -- the foreign leader he has come to work so closely with.
As Europe faces an uncertain future with President-elect Donald Trump, it is Merkel who stands in direct opposition to him.
She is now the strongest leader in Europe to defend the integrity of the European Union and the liberal "European values" that Orban and others have railed against.