Australia's biggest city, Sydney, traditionally the first to host a major event to ring in the New Year, welcomed 2016 with spectacular midnight fireworks as crowds thronged to harbourside vantage points.
Pyrotechnics burst over the city in a colourful display which was expected to draw more than one million people, ahead of the chimes of midnight moving across Asia, the Middle East, Africa, Europe and finally the Americas.
In the heart of Europe, annual festivities and fireworks in Brussels have been cancelled as the Belgian capital -- home to NATO and the European Union -- remains on high alert.
"It's better not to take any risks," mayor Yvan Mayeur said.
Belgian officials are battling terror on two fronts -- with police on Thursday detaining six more people over an alleged New Year attack plot in Brussels as well as arresting a tenth suspect over last month's massacre in Paris.
Belgian police detain six people over New Year's attack plot
Officials said two men had already been formally charged with terrorism-related offences and that police detained six more 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.
"The people of Paris and France need this symbolic passage into the New Year," said Paris mayor Anne Hidalgo.
"After what our city has lived through, we have to send a signal to the world," she told the weekly Journal du Dimanche.
High security
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 centre 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 revellers 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, spokesperson 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 percent 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.
Belgian police detain six people over New Year's attack plot
Berliners will do better with about a million expected at the Brandenburg Gate for a free mega-street party.
Party at the pyramids
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 Hamas has banned public New Year's Eve parties.
Police spokesperson Ayman al-Batinji told AFP 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.
Celebrations away from the palm-fringed beaches will be muted, however, as people remember almost 4,000 victims of the epidemic.
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.
This year's show includes performances by artists Demi Lovato, Daya and Jessie J.
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