Celebrations have begun as people around the world ring in the New Year.
From Sydney to Pyongyang, festive crowds gathered to say goodbye to 2016, a tumultuous year in global politics.
Earlier, Auckland in New Zealand became the first major world city to welcome the New Year.
Many cities around the world have stepped up security for New Year’s Eve celebrations, after a year in which attackers drove lorries into crowds in Berlin in Germany and Nice, France.
Thousands of extra police will be on duty in London and other cities.
In Paris, Madrid and New York, concrete barriers and heavy goods vehicles will be used to block off central squares where crowds gather to celebrate.
Some 17,000 police officers will be on duty in the Turkish city of Istanbul, with some disguised as Santa Claus and street vendors, the state-run Anadolu news agency reported.
The iconic midnight fireworks display at Sydney Harbour in Australia paid tribute to Prince and David Bowie, two music superstars who died in 2016.
“This year, sadly, we saw the loss of many music and entertainment legends around the world,” fireworks co-producer Catherine Flanagan said.
“So celebrating their music as part of Sydney New Year’s Eve fireworks displays is an opportunity to reflect on the year that has been and what the future may hold.”
Seven tonnes of fireworks were set off in two displays watched by about one and a half million people.
Pacific islands including Samoa, Tonga and Kiribati entered 2017 at 10:00 GMT, followed an hour later by Auckland, where fireworks erupted from the 328m (1,080ft) tall Sky Tower in the city centre.
On Friday a man in Sydney was charged in connection with threats made against Sydney’s New Year’s Eve celebrations.
Police said he was charged with a “crimes act offence, but not a terrorist offence” and there was no continuing threat to the community.
A “leap second” will be added to the countdown in countries in the GMT timezone including the UK to compensate for a slowdown in the Earth’s rotation.
The extra second will occur as clocks strike midnight and a time of 23:59:60 GMT will be recorded, delaying 2017 momentarily.
This is required because standard time lags behind atomic clocks.
