In the face of November's terror attacks, tightened security put a damper on the party in Europe with fireworks cancelled in Brussels and Paris.
Yet at the stroke of midnight the skies still lit up with pyrotechnics in Sydney, traditionally the first to host a major New Year's bash, as crowds thronged to waterside vantage points.
‘At the stroke of midnight the skies still lit up with pyrotechnics in Sydney, traditionally the first to host a major New Year's bash, as crowds thronged to waterside vantage points.’
Tens of thousands of revelers gathered on either side of Hong Kong's iconic Victoria Harbor, which was bathed in a dazzling fireworks display.
The chimes of midnight will move across Asia, the Middle East, Africa, Europe and finally the Americas.
In the heart of Europe, more than 100,000 police were to be deployed throughout France to guard celebrations that come six weeks after the jihadist attacks in Paris.
While annual festivities and fireworks in Brussels were cancelled as the Belgian capital - home to NATO and the European Union - remains on high alert.
Brussels mayor Yvan Mayeur said, "It's better not to take any risks."
Belgian officials are battling terror on two fronts - with police on Thursday, December 31, 2015, detaining six more people over an alleged New Year attack plot in Brussels as well as arresting a tenth suspect over the Paris attacks. Police detained six people Thursday for questioning over an alleged plot to strike "emblematic sites" in the Belgian capital during the end-of-year festivities.
Paris, still reeling from the November 13 slaughter of 130 people, has also cancelled its fireworks display.
But authorities agreed France's biggest public gathering since the attacks can go ahead on the Champs Elysees avenue, with bolstered security.
Paris mayor Anne Hidalgo said, "The people of Paris and France need this symbolic passage into the New Year. After what our city has lived through, we have to send a signal to the world."
Hong Kong, Beijing, Singapore and other Asian cities may rival Sydney's pyrotechnic splash, but Brunei will offer a sober evening after banning Christmas in a shift to hardline Islamic law.
Jakarta remains on high alert after anti-terror police foiled detailed plans for an alleged New Year suicide attack in the Indonesian capital.
Turkish police have detained two Islamic State suspects allegedly planning to stage attacks in the center of the capital Ankara which is expected to be packed on New Year's Eve.
Meanwhile, in Moscow police will for the first time close off Red Square where tens of thousands of revelers traditionally gather.
"It's no secret that Moscow is one of the choice targets for terrorists," Moscow mayor Sergei Sobyanin said recently.
In Britain, Scotland Yard said there will be around 3,000 officers across central London in what is reported to be an unprecedented anti-terror security effort.
"Our plans are purely precautionary and not as a result of any specific intelligence," said Superintendent Jo Edwards, spokeswoman for Scotland Yard.
Fireworks were banned in towns and cities across Italy, in some cases because of a recent spike in air pollution but also because of fears that, in the current climate, sudden loud bangs could cause crowds to panic.
The number of police on duty in Italy has been increased by 30% compared to last year although the Interior Ministry stressed, "There has been no specific alert."
In Madrid, thousands of people will flock to Puerta del Sol square, however police will limit the number allowed in to just 25,000.
Berliners will do better with about a million expected at the Brandenburg Gate for a free mega-street party.
Cairo meanwhile is trying desperately to attract tourists to bolster the economy.
The government is staging celebrations in front of the pyramids near the Egyptian capital, with ambassadors, artists and intellectuals all invited.
Egypt has been in turmoil since the 2011 uprising but was further hit by the October 31 crash of a Russian airliner over the Sinai killing 224 people.
On the nearby Gaza Strip, the Islamist group Hamas has banned public New Year's Eve parties.
Police spokesman Ayman al-Batinji said, "Such celebrations were incompatible with our customs, traditions, values and the teachings of our religion."
In stark contrast, Sierra Leone's capital Freetown is hoping to reclaim its mantle as host of the best beach parties in Africa after Ebola scared people away.
The city of 1.2 million was deserted 12 months ago during the worst Ebola outbreak ever recorded.
"This New Year's Eve I am going to dance and party until the cock crows," said 35-year-old Franklyn Smith.
In New York, despite a pledge of tight security for Times Square, another million people are expected to turn out to see the ball descend.