Tens of thousands of people have seen in the New Year with spectacular fireworks displays in London, Edinburgh and across the U-K.
There was a huge police presence on the streets of London as spectators from nearly 100 countries flocked to the Thames to watch the night sky light up as Big Ben struck midnight.
Celebrations featured the music of artists who died in 2016, including George Michael and David Bowie.
Hundreds of thousands of people have witnessed the descent of the kaleidoscopic New Year's Eve ball in Times Square, celebrating a century-old New York tradition.
As many as two million people, surrounded by a ring of 40-tonne sand trucks and 7-thousand police, gathered to watch the glittering sphere complete its minute-long drop.
At the stroke of midnight, it touched home, illuminating a giant "2017" sign and sending a shower of fireworks into the sky.
Brooke Muse says it's been a dream for her to celebrate in Times Square.
"I just wanted to come here and check it out. I wanted to see this ever since I was a kid. It is very glorified to us, seeing the ball drop and seeing everybody get together. And it such a warming experience -- not too warm, but a warming experience for everybody to be here."
In Russia, crowds gathered as the Moscow sky was lit up by fireworks.
People from all over the world chose Berlin to welcome 2017 with a big party at the city's landmark, the Brandenburg Gate.
Security has been tight after a recent attack which killed 12 people - when a 24-year old Tunisian ploughed a hijacked truck into a crowd of Christmas market visitors.
Berlin police deployed 1,700 extra officers and set up armoured cars and concrete barriers to block off the area.
A massive security presence also met crowds who flocked to Paris' iconic Champs-Elysees Avenue for celebrations.
The large crowd witnessed a spectacular light show projected onto the Arc de Triomphe as well as a fireworks.
Close to two million people packed Rio de Janeiro's scenic Copacabana beach to ring in 2017 with a toast under the city's massive fireworks display.
Many Brazilians followed the traditional custom of skipping over seven waves, throwing flowers into the ocean and making wishes.
This reveler, Andrea, had a big wish for the new year - more respect for transgender people.
"I wish for a less prejudiced world, especially against transgender people like us who pay a price for being so real as to accept our gender identity. So, that's what I wish for. A little more respect as human beings in general. Of course."
Tens of thousands New Year revelers gathered at Tokyo's Shibuya crossing to join the mass countdown.
Egypt celebrated with a fireworks display and a countdown at the Great Pyramids of Giza, while in Helsinki, the fireworks also signified the beginning of the centenary year of Finnish independence.
But the year end countdown came with protest action in South Korea, as demonstrators gathered in Seoul to demand President Park Geun-hye's immediate resignation.
And Australia certainly didn't disappoint.
Sydney welcomed in the New Year with a display of light, colour and music - as a fireworks display thrilled capacity crowds.
An estimated 1.5 million people packed the foreshore.
Almost half a million people packed Melbourne's C-B-D to watch the fireworks.
Meanwhile, Prime Minister Malcolm Turnbull has shared a serious New Year message - turning his attention to terrorism.
He says it will not succeed in dividing Australians.
"Those who have sought to divide us have failed, just as those who try to divide us in the future will fail. And that's because we remain united in our determination to maintain our Australian values and our Australian way of life. Freedom, diversity and security - these are great Australian strengths. And they are built upon a foundation of mutual respect."
A strong warning from French President Francois Hollande over the risks of nationalism.
In his last New Year address ahead of the election of his successor, Mr Hollande has urged France not to pursue isolationist policies.
"Democracy, freedom, social rights - all of that becomes vulnerable. We saw it in the United Kingdom with Brexit and in the United States during the election in November. We see it across our continent with the rise of extremism."
Outgoing United States President, Barack Obama, has wished a Happy New Year to Americans for the last time in his capacity as the U-S leader.
He's urged Americans to stay united following the 2016 presidential elections.
"And to keep America moving forward is a task that falls to all of us. Sustaining and building on all we've achieved - from helping more young people afford a higher education, to ending discrimination based on pre-existing conditions, to tightening rules on Wall Street, to protecting this planet for our kids - that's going to take all of us working together. Because that's always been our story - the story of ordinary people coming together in the hard, slow, sometimes frustrating, but always vital work of self-government. "
Russia's President, Vladimir Putin has also given his New Year message.
" It wasn't easy, but the difficulties that we faced have unified us. They've motivated us to discover huge reserves of our capacity to move forward. The main thing is that we believe in ourselves, in our strength, in our country."
Meanwhile, British Prime Minister Theresa May has called on citizens to unite and overcome differences after last year's divisive Brexit vote.
She says it's a time to reflect on what has passed and to look ahead to the opportunities to come.
