One year after full-scale war returned to Europe for the first time since World War II, the invasion of Ukraine grinds on with no end in sight.
Under the cover of darkness on February 24, 2022, Vladimir Putin acted on a long-held ambition, rolling his tanks across the border and disrupting the lives of 44 million people.
Ukrainians woke up to the sound of panicked texts and calls, and air raid sirens blaring over the capital, the first signs their fragile peace with Russia was broken.
Ordinary citizens with normal, everyday lives were suddenly making heartbreaking decisions over whether to stay and fight or undertake the treacherous journey to a border crossing.
In the space of a fortnight, Natalie Taranec went from teaching at a school in Kyiv to making a desperate dash to the sanctuary city of Lviv and fleeing to another country.
"Leaving Ukraine [is] done with a heavy heart," she said as she packed her bags and prepared for a long drive to the border with her husband.
Among the great uncertainties they faced as they made their decision to leave was about how the invasion would unfold and ultimately end.
One year on, the same question still looms large for many.
Ask any analyst or observer how they think the war in Ukraine will play out, and they'll tell you their guess is only as good as the next offensive.
Less than 12 months ago, few could have imagined the invasion continuing until today, much less predicted its conclusion.
With so much of Ukraine's fate still uncertain, analysts say all outcomes remain possible.
A highly motivated Ukraine may continue to defy the odds, recapturing the land it lost after February 24.
Russia could make a push for more land or the flow of weapons to Kyiv could be halted, bringing forward a stalemate.
Or the war could drag on for years and years at a low ebb. Or it could all end in a small room with both sides laying out their terms for peace.
While the West believes it will be up to Ukraine to decide its future, there is no denying the outcome of the war will have far-reaching consequences for Europe and the rest of the world.
Everyone has a stake in the endgame.
The state of the war
In a two-hour address on Tuesday night, Vladimir Putin gave no indication the war would end any time soon, promising to continue Russia's offensive against its neighbour "step by step".
"I want to repeat. [The West] started the war. And we used force, and are using force, to stop it," he said.
Russian and Ukrainian forces have essentially been locked in a slow, grinding fight since November, particularly around the gateway to the north and central parts of Luhansk, as the war shifted into positional warfare.
While Ukrainian forces still have momentum, Russia currently controls about 18 per cent of Ukraine, including much of Donetsk and Luhansk in the east, as well as Crimea, which it illegally annexed in 2014.
It has also spent the past two months systematically targeting Ukrainian infrastructure, devastating the country's power grid and putting its healthcare services at risk.
By the end of last year, the United Nations had recorded around 18,000 civilian casualties in Ukraine and 50 per cent of its energy infrastructure as destroyed or damaged.
Russia has also suffered immense losses on the battlefield, with US officials estimating a toll of almost 200,000.
Ukraine's resistance and willingness to fight remains strong, but — if there is a Russian offensive on the horizon as some are predicting — their fortitude will once again be put to the test.
For now, Volodymyr Zelenskyy maintains he will continue to fight to the bitter end.
Mr Putin has suggested the same, claiming he is ready to resume nuclear weapons testing after suspending participation in New Start, the last remaining nuclear arms control treaty between Russia and America.
So, what will unfold next in the war and are there any signs it is reaching its conclusion?
These are some potential scenarios.
Ukraine recaptures its territory
Throughout the war, Western governments have continued to supply aid and weapons to Ukraine and, if that continues, Kyiv's forces could translate that into more battlefield success.
"It's certainly what the Ukrainians are betting on," International Crisis Group's director of the Europe and Central Asia program, Olya Oliker, said.
Ukraine is in a strong position, but a number of things have to line up perfectly for its soldiers to be able to recover all the territory they have lost by the end of this year.
The commander-in-chief of Ukraine's armed forces said in December that his country needed 300 tanks, 600-700 armoured fighting vehicles and 500 howitzers to push the Russians back from their fortified positions.
Analysts say its forces also require more troops and would need to withstand an expected Russian onslaught in spring, between March and May.
If Ukraine manages to clear some of those hurdles, its forces could be in a position by July to retake large portions of land, according to the Royal United Services Institute's former director, Professor Michael Clarke.
While a happy outcome for Ukraine, victory would be contingent on the flow of equipment and aid from the West continuing, which rests on two key factors beyond Kyiv's control: capacity and political will.
After years spent scaling-back artillery, ammunition and tank investments, Europe has cleared out old warehouses to supply Ukraine with the weapons it wants and needs to fight Russia.
Both sides are burning through arsenal at breakneck speed, setting off a mad scramble for remaining Soviet-era equipment such as S-300 air defence missiles, T-72 tanks and artillery shells.
"The current rate of Ukraine's ammunition expenditure is many times higher than our current rate of production. This puts our defence industries under strain," NATO Secretary-General Jens Stoltenberg warned this month.
Smaller NATO countries have reportedly exhausted their supplies, leaving a shrinking pool of nations to step up and fill the gap.
Germany and France have announced more support through air missile systems and AMX-10 RC light armoured vehicles, while the US tipped in another $US3.75 billion in new military assistance last month.
US President Joe Biden's recent unannounced trip to Ukraine was also intended to rally NATO support for Ukraine, after insisting there would be no backing down from what he's portrayed as a global struggle between democracy and autocracy.
It comes amid a deepening global divide on the conflict and concern that public support and political will may wane the longer the war drags on.
While Americans back providing aid for Ukraine, a recent Pew Research Poll found nearly a quarter believe the country is providing too much support to Ukraine.
And some prominent Republicans — who took over the House from the Democrats in January — have called for an end to US military and other assistance to Ukraine.
"The Ukrainians, I think, have confounded most expectations — [but], I think, this is all contingent on Western support continuing," King's College London professor of conflict and security Tracey German said.
Without ongoing funding and supplies, analysts warn the Ukrainians could falter, turning the war in Russia's favour.
Moscow snatches victory
All signs are pointing to a renewed push from Russian forces, likely involving thousands of soldiers in battalion and brigade-sized attacks, as Moscow continues to hammer Ukraine's energy network.
Mr Putin has already annexed the regions of Donetsk, Luhansk, Kherson and Zaporizhzhia through so-called referendums after pulling back troops to regroup in eastern Ukraine.
Over the winter, Russia's army had the opportunity to stabilise its front lines and develop new ones, thanks to an injection of fresh recruits from its partial mobilisation in September.
Ukrainian officials believe an emboldened Russia is preparing for another offensive as early as today, having begun the preliminary phase earlier this month.
The Russian side hasn't escalated as much as it can, analysts say, and another offensive aligns with Mr Putin's strategy to double down when backed into a corner.
"[Putin] can't stop, he can't go back," the Centre for Strategic and International Studies' senior advisor and retired Marine colonel Mark Cancian said.
Russian nationalist voices have already expressed skepticism in Russia's ability to launch a successful offensive, but Ukraine's defence minister, Oleksii Reznikov, says Moscow could "try something" to mark the anniversary of its initial invasion.
A possible escalation could involve Russian forces turning the tables on the battlefield and making a push for the south of Ukraine, Professor Clarke said.
The eastern city of Bakhmut, the small town of Vuhledar, Kharkiv and Zaporizhzhia — the gateway to the south — could all be in their sights, the BBC has reported.
"If the Russian spring offensive was successful … they could possibly take all of the area west and [to] the east of the Dnieper River, and then make a puppet state out of what's left of Ukraine," Professor Clarke added.
Or Mr Putin could resort to more-drastic measures, including the use of nuclear weapons, Dr Oliker warns. Nothing is off the table.
It is still unclear what victory would look like for Mr Putin, who has continued to push the false narrative that the West is to blame for the war and framed the invasion as a global conflict.
Analysts say conquering pieces of Ukraine wouldn't necessarily mean an end to the fighting.
"[Russia is] facing three or four generations, 60 or 80 years, of guerilla war, because they're up against a population of 44 million people who are now completely and utterly Ukrainian men," Professor Clarke said.
A stalemate and an armistice
One other possibility is that both sides become exhausted after an inch-by-inch fight, and decide to come to an agreement.
Chairman of the US Joint Chiefs of Staff General Mark Milley has previously suggested there was no military solution to the Russia-Ukraine conflict and diplomacy was needed to end the war.
As painful as it is to make compromises in a negotiated settlement, Mr Cancian says Kyiv and Moscow may one day decide peace is the only way forward.
The West — the US, NATO and/or a handful of European countries — could play a hand in hastening that decision, perhaps by offering Ukraine an ultimatum.
However, the terms for how the fighting could end are murky. The current outlook for a negotiated deal would likely involve Ukraine ceding some territory to Russia, analysts say.
Mr Zelenskyy has so far ruled this out as a possibility, proposing a 10-point "formula for peace," which includes demands for a full withdrawal from Ukraine's territory.
"From a Ukrainian perspective … after the losses that they have endured, particularly over the last year, the question will be … 'Why would they want to seek to negotiate over what is their recognised territory?'" Ms German said.
Neither side has been wiling to come to the negotiation table since the beginning of the war, dashing any hopes for an end to the fighting any time soon.
However, if the war were to drag on this year and into next year, the reasoning could change.
Ukraine could be in a strong position to negotiate once it gets back all of its territory, "including most of what it lost in the Donbas in 2014, with special arrangements made for plebiscites," Professor Clarke said.
Although he added that discussions around Crimea would likely have to be settled separately, possibly going to an international tribunal for discussion and a process of continuing negotiation.
Both sides could engage in a "step-by-step approach to a temporary peace", unfolding in a similar way to previous conflicts, including Cyprus after 1974 and Korea after 1954, Professor Clarke added.
Any progress towards talks would likely start with a ceasefire or a similar type of temporary arrangement that would enable both sides to suspend fighting, the analysts suggest.
A ceasefire would give the Ukrainians a reprieve without backing Mr Putin into a corner, preventing a possible escalation in which he resorts to extreme measures such as attacks on Western energy infrastructure or the use of nuclear weapons.
Sanctions would remain and borders would still be in dispute until a final agreement is reached, which could take years and multiple rounds of ceasefires.
In the meantime, the costs of the war would continue to weigh heavily on Russia, possibly weakening Mr Putin's internal support.
Putin is ousted and the Russian state collapses
As the war drags on, there is growing debate over whether Mr Putin will be around long enough to oversee its end.
The Russian leader's future may depend on the country's powerful security forces, such as those led by Yevgeny Prigozhin or Chechen leader Ramzan Kadyrov.
Mr Prigozhin's guns for hire have played a critical role in keeping the war going against a backdrop of morale problems, strategic blunders and lack of adequate training.
However, the man dubbed "Putin's chef" has also been a vocal opponent of the Kremlin's inner circle in recent months in a sign that power may be shifting among Russia's political class.
"The elites and potential successors are watching [Putin's] every military move, but they can already see that he has no place in their post-war vision of the future," Russian journalist Andrey Pertsev wrote in his analysis for the Carnegie Endowment.
"His sole remaining function in their perception of the new era of peace will be to nominate a successor and leave the stage."
Professor Clarke said the downfall of Mr Putin was only a matter of time and would likely be brought about from within the military and Russia's security service, with the support of oligarchs fed up with the Kremlin.
Some observers say the likelihood of negotiations between Russia and Ukraine would be more favourable under a different leader.
While the invasion of Ukraine was started and waged by Mr Putin, Alexei Navalny says the real war party is the entire elite and the system of power itself, which is an "endlessly self-reproducing Russian authoritarianism of the imperial kind".
Mr Putin's exit would not end the war in Ukraine because the Russian leader would likely be replaced by another pro-war nationalist, Professor Clarke said.
"So, the war will go on with somebody else," he said.
Forcing Mr Putin out of the Kremlin also carries enormous risks for whoever takes over, by hastening the Russian state's ruin.
If there was no clear successor, Mr Putin's departure could spur on a brutal power struggle among pro-war, right-wing nationalists, authoritarian conservatives and a murky anti-war movement.
This, in turn, would likely weaken the regime and distract Russia from what remains of its war effort.
The war with no end
One final scenario that many have predicted throughout the war is a grinding conflict between Ukraine and Russia lasting many years.
The "special military operation" in Ukraine has already beaten most analysts expectations and, with more offensives planned for this year, there appears to be no end in sight.
The longer the war drags on, there is an increased chance it may slow to "more of a nasty simmer", like the one prior to the full-scale invasion in February, Ms Oliker says.
"It's actually much more sustainable for both countries," she said.
"If it's a smaller front-line, and less fighting, they'd both be building up and looking for a way to break through. But, at least for a while, they'd have a way to rebuild.
"And you could even imagine some kind of, if not a ceasefire, but something that is at least a massive dialling down. But that will be temporary."
A similar situation emerged after the fighting in Ukraine in 2014, with the unresolved conflict featuring a form of continued Russian occupation for many years.
However, there is a risk if this were to happen that Russia would launch another invasion in future, once it had time to replenish its stocks.
What the endgame means for the world
The Ukraine war has had tremendous ripple effects throughout the world's economy by driving up gas prices and inflation rates, impeding the flow of goods, exacerbating world hunger and stretching the entire humanitarian system.
European security was also fundamentally changed by Russia's invasion on February 24 and many states outside of Russia and Ukraine have a stake in its outcome, analysts said.
At the core of why governments are defending Ukraine is the conviction that an emboldened Russia is dangerous for the rest of Europe and, possibly, the world.
"The price we pay is in money, while the price the Ukrainians pay is in blood. If authoritarian regimes see that force is rewarded, we will all pay a much higher price," NATO General Secretary Jens Stoltenberg said at the end of last year.
"And the world will become a more dangerous world for all of us."
If the West remains united with Ukraine, it could make the costs of the war so insurmountable for Russia that it breaks the level of commitment of its political elite.
Mr Putin, on the other hand, is banking on support weakening over time, giving him an opportunity to snatch victory from the jaws of defeat.
Ultimately, there is hope there will one day be an end to the bloodshed.
Although it is tempered by a grim knowledge that one wrong move could escalate the conflict into a situation once considered unthinkable.
A tit-for-tat nuclear altercation is the sort of grim scenario you could imagine not even Mr Putin would desire.
However, with the stakes this high, it's impossible to rule out.
