Finland's
Sanna Marin is to become the world's youngest prime minister at the age of 34.
The transport minister was picked by her Social Democratic party after its leader,
Antti Rinne, quit as PM. She will be sworn in this week.
She will lead a centre-left coalition with four other parties, all headed by women, three of whom are under 35.
Mr Rinne stepped down after losing the confidence of a coalition member over his handling of a postal strike.
When she takes office, Ms Marin will be the world's youngest sitting prime minister. New Zealand PM Jacinda Ardern is 39, while Ukrainian premier Oleksiy Honcharuk is 35.
She will be the third female prime minister in the Nordic country.
What is Ms Marin's background?Media reports say Sanna Marin was raised in a "rainbow family", living in a rented apartment with her mother and her mother's female partner. She told the Menaiset website (in Finnish) in 2015 that as a child she felt "invisible" because she was unable to talk openly about her family.
But she said her mother had always been supportive and made her believe she could do anything she wanted.
She was the first person in her family to go to university.
Ms Marin rose quickly through the ranks of the Social Democrats, heading the city administration in Tampere at the age of 27 and becoming an MP in 2015.
She has been transport and communications minister since June and has a 22-month-old daughter.
Bubbling to the surfaceAnalysts say it may be a coincidence that Finland now has a female prime minister and four party leaders in the ruling coalition who are women, but gender equality is a big issue in Finland and women in Finnish politics have been bubbling under for a long time.
A couple of decades ago, researchers noticed that many parties had young women in prominent positions, either second or third in command, Reetta Siukola, development manager at the Centre for Gender Equality Information, told the BBC.
There have been two female prime ministers this century, though both were short-lived.
Indeed women, especially younger women, have always been active in Finnish politics, and in recent years the public has come to expect 40% or more women ministers in its governments.
That changed in 2015, when the relatively male-dominated centre-right government of Juha Sipila took power - only 36% of its ministers were female.
Combined with the rise of the #MeToo movement worldwide, this was a huge wake-up call for gender equality advocates prompting a very active civil society discussion, Ms Siukola says.
What direction is Ms Marin likely to take?There are unlikely to be any major policy changes, as the coalition agreed a programme when it took office.
However, Ms Marin, who won the vote for prime minister by a narrow margin, made it clear it would not be business as usual.
"We have a lot of work to do to rebuild trust," she told reporters.
She brushed away questions about her age, saying: "I have never thought about my age or gender. I think of the reasons I got into politics and those things for which we have won the trust of the electorate."
The Social Democrats emerged as the largest party in elections held in April, and so can appoint the prime minister who leads the coalition government.
Mr Rinne stepped down after a plan to cut wages for hundreds of postal workers led to widespread strikes. Coalition member, the Centre Party, said it had lost confidence in him.
However, he is as yet still leader of the Social Democrats.
Meanwhile, the Centre Party said Katri Kulmuni would be named as finance minister. The 32-year-old took over as its leader in September.
The other three leaders were ministers in Mr Rinne's government and are expected to continue in their posts - the Left Alliance's Li Andersson as education minister; Green leader Maria Ohisalo as interior minister; and Anna-Maja Henriksson of the Swedish People's Party as justice minister.
Finland currently holds the European Union's rotating presidency, and MPs are likely to approve the new government ahead of the EU summit in Brussels on 12 December.