Fireworks have lit up the skies over some of the world's most iconic landmarks as people across the globe gather to welcome the new year. From Sydney to Moscow, Paris to New York, crowds said goodbye to 2016, a tumultuous year in global politics.
Many cities stepped up security for New Year's Eve celebrations, after a year in which attackers drove lorries into crowds in Nice and Berlin. Thousands of extra police have been on duty in London and other cities. But it did not stop tens of thousands lining the River Thames to watch a fireworks display with one very clear message after the country voted to leave the European Union: "London is open."
It also failed to dampen spirits in Paris, where about 500,000 people poured into the Champs-Elysees, where the Arc de Triomphe was lit up with a colourful countdown and the word "welcome" in dozens of languages.
Revellers in Berlin were undeterred by the recent terror attack at a Christmas market, gathering for a series of concerts before a midnight fireworks display.
Some 2,000 police watched over the around two million people enjoying a fireworks display on Rio de Janeiro's Copacabana Beach which had been shortened this year due to a severe economic crisis.
But the 17,000 police officers on duty in the Turkish city of Istanbul were unable to prevent an attack on a nightclub less than two hours into 2017, which left at least 39 dead.
Pacific islands including Samoa, Tonga and Kiribati were the first to enter 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.
The iconic midnight fireworks display at Sydney Harbour in Australia paid tribute to Prince and David Bowie, two music superstars who died in 2016. Seven tonnes of fireworks were set off in two displays watched by about one and a half million people.
A "leap second" was added to the countdown just before midnight in countries in the GMT timezone, such as the UK, to compensate for a slowdown in the Earth's rotation.
The extra second occurred just before clocks struck midnight and a time of 23:59:60 GMT was recorded, delaying 2017 momentarily.
This is required because standard time lags behind atomic clocks.