The killing of Russia's ambassador to Turkey on Monday evening might have prompted knee-jerk comparisons to the 1914 assassination of Archduke Franz Ferdinand, but it almost certainly won't spark a World War I-type conflict. The lethal truck attack that killed 12 in Berlin a few hours later, however, could ratchet up the prospect of yet another political shock in Europe.
The year now concluding looks set to keep throwing out unexpected, often brutal surprises right to its end. If 1989 -- the year the Berlin wall fell -- was the point at which globalisation, liberal democracy and the Western view of modernity was seen to triumph, 2016 might yet be seen as when the wheels came off.
That may be a dramatic overstatement. However, the electoral surprises of the Brexit vote and the election of Donald Trump -- as well as dozens of other examples across the globe -- are stark reminders of just how much consensus has unraveled. The next year could see a step back towards moderation. But it could equally see things spiral further out of control.
The assault on a Christmas market in the German capital has made the return of the far right to power in Germany more plausible -- even if it still looks unlikely to happen in next year's national vote. The Berlin deaths could also boost the chances of far-right National Front leader Marine Le Pen in France's 2017 presidential election.
It is possible, of course, that the forces of moderation might stage something of a recovery next year -- as we saw in Austria's presidential election, even this year extremists have not always won.
What 2016 has demonstrated most, however, is that nothing is truly unthinkable anymore -- or that a host of options previously judged unthinkable are much more likely than anyone previously thought.
It is also clear that we have yet to see the true implications of much that happened in 2016. President-elect Trump is not yet in the White House, but he -- and particularly his Twitter feed -- is already having a dramatic effect.
It's hard to predict exactly what that might mean, but the indication so far is that this will be a very different presidency. It may well, of course, mean temporarily better relations with Russia -- Mr Trump's comments in the aftermath of Monday's attacks explicitly tied the Ankara attack to that in Berlin and suggested he intends to follow through on talk of much closer collaboration with Russia, particularly on fighting Islamist militancy. That may also imply some kind of grand bargain on Syria, particularly with the fall of Aleppo making any opposition victory even more implausible.
A Trump administration, however, may well swiftly find itself much more greatly at odds with China. Last week's spat over the Chinese seizure of a US underwater drone in the South China Sea may be a sign of things to come on that front.
The one thing that has cemented Beijing into the international system over the last 25 years, after all, has been that it has benefited greatly from being part of an increasingly free international trading system -- something Mr Trump clearly intends to push back against, if not dismantle entirely.
If British Prime Minister Theresa May is to be taken at her word, then in 2017 Brexit will really begin to mean Brexit insofar as the UK will move to trigger Article 50 to quit the European Union.
No one really knows what that will mean. In part, that is because no one has any concept of what the European continent will look like politically by the end of next year. The Berlin attack, whether the perpetrator is eventually found or not, will almost certainly ramp up political pressure on Chancellor Angela Merkel for her policies on migrants, just as attacks in France have boosted Ms Le Pen's National Front.
It seems less likely for now, that Alternative for Deutschland -- the far-right party that has taken up to a third of the vote in several German states this year -- could itself topple Ms Merkel. But the party could do well enough that she is replaced by another more moderate figure.
A European move to the far right is not inevitable; the failure of the Austrian far right to gain the presidency demonstrates that. Still, even the prospect that France, Germany and potentially other states might see the far right take a dominant if not controlling role makes the continent a very different place.
If nothing else, 2017 looks set to see a major push back against the European -- and to an extent much broader -- liberal ideal of open borders and trade. The EU itself may not survive that.
Nor, for that matter, can the ongoing endurance of the always troubled single currency. The Italian referendum earlier this month has left its government in a state of crisis, with the real prospect that the anti-euro "Five Star" movement might take control. An Italian exit might well spell the end for the euro -- at the very least, it would make Brexit seem relatively small fry.
On Europe's eastern flank, meanwhile, Russia waits -- sometimes interfering to try to exacerbate political chaos and tilt things its way. Following the Trump victory, the long-term future of Nato is also murky.
For all the worries of inadvertent conflict after Monday's assassination in Ankara, it's particularly striking that Turkey, Russia and Iran made it clear they were making common cause and continuing with the meeting in Moscow to discuss Syria. Turkey might still be a Nato member, but under President Recep Tayyip Erdogan may also be moving closer to Vladimir Putin.
This has been a complicated year. Don't count on 2017 being any easier.
Peter Apps is a Reuters global affairs columnist.