When Finland's Prime Minister, Sanna Marin, and Sweden's leader, Magdalena Andersson, met for a key press conference in April, it became a defining moment for both countries.
For decades, Finland and Sweden had clung to their non-militarily-aligned status, pursuing close ties with Europe, while maintaining a cordial relationship with their eastern neighbour, Russia. But the war in Ukraine changed everything.
While Ms Marin refused to give any kind of timetable on the decision at the time, she hinted at the press conference that Finland's bid would happen "quite fast".
Her prediction came true. Within a month, the proposal was before Finland's parliament and signed off, and this week the full membership of NATO agreed to formally invite both countries to officially join the alliance.
Political observers say the decision is the "most important moment of Finnish history, at least in security policy".
Overseeing this radical change is 36-year-old Ms Marin, a feminist environmentalist whose rise to the top job has been seen as just as monumental.
Ms Marin has faced her share of challenges while in the top job, including a global pandemic and a fragile political coalition. However, a humiliated Vladimir Putin could pose a new, unpredictable risk.
After Finland announced its bid in May, Russia bit back with a foreboding promise, hinting it may be forced to take "retaliatory steps".
So far, Mr Putin's response has been measured, but he warned his neighbours on Friday that if there were any threats to Russia, he would be "compelled to respond in kind".
"If NATO troops and infrastructure are deployed, we will be compelled to respond in kind and create the same threats for the territories from which threats towards us are created," he said.
It appears unlikely to dampen the resolve of either the Finnish or Swedish leaders. From the beginning, Ms Marin has declared she is prepared to make compromises: "We have to be ready to pay a price to put an end to the war."
'A cashier can become even a prime minister'
While a small country, with a population of just 5.5 million people, Finland punches above its weight on gender equality, wellbeing and education.
Its youngest-ever leader was shaped by the strength of the country's expansive welfare state.
Raised by her working-class mother and her same-sex partner, Ms Marin came from a modest background, becoming the first in her family to finish high school and graduate from university.
She says it was her working-class upbringing that sparked her desire to run for government.
"I have been able to live a safe childhood, get an education and pursue my dreams," she once wrote.
"Making it possible for everyone has driven me into politics."
Ms Marin started work at 15 at a bakery and distributed magazines to earn extra cash. But it was her job as a cashier that was once mocked by Estonia's interior minister, who ridiculed her as a "sales girl" and questioned her fitness to run a country.
"I'm extremely proud of Finland. Here, a poor family's child can educate themselves and achieve their goals in life. A cashier can become even a prime minister," Ms Marin clapped back in a tweet at the time.
At just 20 years of age, Ms Marin entered politics, quickly moving up the ranks of the Social Democratic Party.
By 27, she was elected to the local council in the southern city of Tampere, an experience that, she says, taught her the "valuable lesson" of reaching across the political divide to form a consensus.
Seven years later, at the age of 34, she made history as the world's youngest leader.
Postal strike controversy sends Marin into top office
Ms Marin's rise into the top office came from an unexpected place: the postal service.
In late 2019, more than 10,000 workers from Finland's state-owned postal service went on strike over a proposal to shift 700 employees onto lower-paid contracts.
The strike lasted for two weeks, plunging the nation into chaos as mail went undelivered and transport workers and airline staff threatened to walk off their jobs in solidarity.
Then-prime minister and Social Democratic Party leader Antti Rinne was skewered for his mismanagement of the whole debacle, and swiftly resigned.
Enter Sanna Marin. The party council chose the first-term MP and transport minister of just six months to take over as leader and prime minister.
At 34 years of age, she became the world's youngest prime minister and Finland's third female leader.
Even so, she has attracted headlines globally for breastfeeding her daughter in parliament and championing parental leave.
In her bid to build a future for Finland where "every child can become anything and every person can live and age in a dignified way", tackling climate change was at the top of the agenda.
"Climate change is the issue that everybody in my generation thinks about. It is the Berlin Wall for our generation and the younger generation than me," she told Vogue magazine.
The new leader also made clear her ambition to move the needle on gender equality by closing the pay gap and encouraging more men to take up parental leave.
Together with the leaders of her four coalition partners — all women, three of whom were also under 35 — she named a cabinet made up of 12 women and seven men.
And, with five parties hashing out their priorities for the nation, negotiation was always going to be a key skill for the Finnish leader.
A leader who knows how to compromise
Ms Marin has joked that, in Finland, decisions are traditionally made at the sauna.
"So now that we have five women in charge, we can all go to the sauna together and make the decisions there," she told TIME magazine in early 2020.
Although, in reality, the partyroom discussions have taken place around a table, there have certainly been some heated debates.
Ms Marin's Social Democratic Party secured enough votes in the 2019 election to become the largest party in the parliament, but only just.
With 40 seats, they were well short of a majority, so swiftly formed a coalition with the Center Party, Green League, Left Alliance and Swedish People's Party.
"In Finland, governments tend to be coalition governments. So we don't have as clearly as in two-party systems … [where] one side [is] normally considered clearly more right-wing and another side considered more left-wing," Mr Teivainen says.
"The Center Party has been in both governments. So, here, they are moderating [the Social Democrats] party towards the [right]."
As leader, Ms Marin has had to navigate the ragtag bunch through their fair share of ideological differences, with clashing views on how best to steer the nation safely through a pandemic and balance the budget.
Late last year, a split emerged between the SDP, Left Alliance and Greens, and the more-conservative coalition partners — the Center Party and SPP — on the financial cost of Finland's ambitious climate change targets.
"[Sanna Marin is] a political player … and the advisers sort of concluded we need the Center Party, so we need to give them something, which will not make the Greens happy, which will not make the left happy, but this is compromise," Mr Teivainen says.
Ms Marin managed to clinch a deal, with the parliament last month signing off on a new climate change act, committing to carbon neutrality by 2035 and carbon negativity by 2040.
Should the fragile alliance fracture beyond repair, the opposition ultra-nationalist Finns Party — the only party to actively campaign against climate action in 2019 — is waiting in the wings.
The second-largest party in parliament after Ms Marin's SDP, the Finns have regularly sought to disrupt the ruling coalition by threatening no-confidence motions.
So far, the coalition has managed to solve most of their differences through compromise.
On the world stage, too, Ms Marin has embraced the art of collaboration, urging her fellow European Union members to unite in overcoming the COVID-19 pandemic.
"If we want to find an agreement, I think everybody has to be flexible … Finland always tries to be compromise-oriented and consensus-oriented," she told reporters at European Council budget talks in early 2020.
But all that may pale in comparison to the greatest test of her leadership yet: a war in Europe.
When Putin came knocking, Marin stood her ground
When Putin marched his troops into Ukraine, he hoped to divide Europe and stymie what he saw as NATO's encroachment.
Instead, as Finland's residents watched the war unfold in Ukraine, there was a sudden push for the country to join the Western military alliance.
"Consensus is critical for a small nation that is next to a big and, unfortunately, warring country," Ms Marin told Ulkopolitiikka-lehti, the Finnish Journal of Foreign Affairs.
The Social Democrats' commitment to the country's non-militarily-aligned status was suddenly put to the test, according to Mr Teivainen.
"The image has been that they are more willing to understand and accept what Russia does, that the Social Democrats have been [less willing] to be very tough on Russia's human rights violations, because you need to play some kind of friendship game there," he says.
"So [Ms Marin has] been much more outspoken there without this dimension, which, on average, has seemed refreshingly good for people here."
However, Mr Teivainen suggests Finland's President, Sauli Niinisto — who is responsible for overseeing the country's foreign policies with the parliament — has also played a key role in Finland's NATO campaign.
Mr Niinisto has also spoken directly with Mr Putin about the move, describing their last discussion as "calm and cool".
And, yet, Finland's accession to the alliance will almost double the land border between Russia and NATO countries.
It also brings the grouping to the doorstep of Russia's military bases on the Kola peninsula and the headquarters of its Baltic Fleet, in St Petersburg.
Whatever happens next, Ms Marin says there is no going back.
"What happened, what Russia did, is a turning point for the entire European family and the whole world," Ms Marin says.
"We see that the old arrangement has been destroyed and there is no return to the former relationship."
