A spectacular fire in one of Dubai's tallest towers and a terror attack red alert in Germany captured the world's attention as the New Year dawned.
But with few exceptions, the celebrations rolled on and while the fire at The Address, a five-star hotel near the Burj Khalifa, the world's tallest building, still raged, the Dubai Media office declared: "New Year celebrations in Dubai will continue as scheduled."
In Munich, police warned about an hour before New Year of a "serious, imminent threat" by the Islamic State (IS) terror group and two railway stations were evacuated.
But despite the call by police for people to stay away from crowds, thousands were still on the streets to see in the New Year with fireworks.
As 2015 drew to a close, many people were bidding a weary and wary adieu to a year marred by attacks that left nations reeling and nerves rattled.
In Bangkok, the site of a deadly bombing months ago, police flanked partygoers. In Paris, people recovering from their city's own deadly attacks enjoyed scaled-back celebrations.
Here is how the world welcomed the New Year.
UNITED ARAB EMIRATES
In the megacity of Dubai, a fire broke out two hours before midnight in The Address hotel, in the area where a massive fireworks display was being prepared.
At least one person suffered a heart attack from the smoke and over-crowding during evacuation, and 14 received minor injuries.
The French are still recovering from the November 13 attacks that left 130 people dead in Paris and authorities prepared for a possible worst-case scenario on New Year's Eve. About 60,000 police officers and troops were deployed across the country, and revellers said that made them feel safer.
Paris cancelled its usual fireworks display in favour of a five-minute video performance at the Arc de Triomphe just before midnight.
Paris mayor Anne Hidalgo said the show was aimed at "sending the world the message that Paris is standing, proud of its lifestyle and living together".
Less than six months after a pipe bomb killed 20 people at the Erawan Shrine in Bangkok, tens of thousands rang in the New Year at the spot with live music and a countdown.
Up to 5,000 police officers were in the area, with bomb disposal experts sweeping the area beforehand.
Security was beefed up in Malaysia's biggest city, Kuala Lumpur, where fireworks greeted 2016 at a historic square and at the Petronas Twin Towers, one of the world's tallest buildings.
Concern in the Philippines on New Year's Eve focused on the use of illegal fireworks, which last year injured more than 850 people. Shopping malls and cities organised displays to discourage people from lighting their own firecrackers.
An annual procession of the Black Nazarene, a black wooden statue of Jesus Christ, was held a day earlier than usual to prevent injuries from mounds of rubbish and unexploded firecrackers that litter Manila's streets after New Year revelries.
New Year's Eve is Japan's biggest holiday, and millions crammed into trains to flee the cities for their home towns to slurp bowls of noodles, symbolising longevity, while watching the annual Red And White song competition on television.
As midnight approached, families bundled up for visits to neighbourhood temples, where the ritual ringing of huge bronze bells reverberated through the chill.
South Koreans marked New Year's Eve with traditional bell ringing ceremonies, fireworks and outdoor music and dance performances. One celebration was organised at a town near the border with rival North Korea to watch one of the ceremonies and wish for peaceful Korean unification.
Pope Francis encouraged humanity to hang on to recollections of good deeds so that gestures of goodness can be seen triumphing over evil.
Francis presided over a prayer service in St Peter's Basilica, where he mused about how people were sometimes driven by "insatiable thirst for power and by gratuitous violence". He said it was impossible to forget "so many days marked by violence, by death, by the unspeakable suffering of so many innocents".
New Zealand, the first nation with a sizeable population to celebrate the New Year, counted down the seconds to midnight with a giant digital clock on Auckland's landmark Sky Tower. Horns blared and crowds cheered as the tower was lit up with fireworks, with colours shifting from green to red to white.
Simultaneous fireworks displays erupted along Sydney's famed harbour, where people crowded on to balconies, into waterside parks and on to boats as they jockeyed for the best view, clinking glasses and whooping with joy as the first pyrotechnics exploded.
An official New Year's Eve celebration was staged near Beijing's Forbidden City with performances and fireworks, and one of China's most popular TV stations broadcast a gala from the National Stadium, known to most as the iconic Bird's Nest.
For safety reasons, Shanghai closed underground stations near the scenic waterfront Bund, mindful of a stampede last New Year's Eve that killed 36 people.
Gaza's Islamist Hamas rulers banned New Year celebrations in the Palestinian coastal enclave. Police spokesman Ayman Batniji said hotels and restaurants were allowed to hold parties a day earlier or a day later.
In Cairo, people put aside fears of the growing number of militant attacks throughout the country to celebrate the New Year.
At the Giza Pyramids, hundreds of people gathered for a fireworks and lighting display at the stroke of midnight.
Police in Kenya, which has been repeatedly attacked by al-Shabaab militants from neighbouring Somalia, urged vigilance as many people prepared to celebrate 2016 in hotels and watch midnight fireworks displays. Unauthorised fireworks were banned as safety hazards "in view of the elevated threat of terrorism", police said.
Rainy weather dampened New Year celebrations in Berlin, where security was tighter than in previous years. Several hundred thousand people still turned out for several minutes of fireworks at the Brandenburg Gate, wishing each other "Froehes neues Jahr" and expressing their hopes for a peaceful 2016.
In Munich, police warned about an hour before the New Year of a "serious, imminent threat" of a terror attack, but thousands of people were still on the streets to meet the New Year.
Major celebrations marked by fireworks spectaculars took place in London, Edinburgh and other big cities despite a terror threat judged to be severe. Police advised revellers not to go to displays without tickets and to be ready to have their belongings searched.
Rio de Janeiro kicked off its Olympic year with a fiesta on Copacabana Beach attended by more than two million people. Brazil's most popular New Year's Eve show was illuminated by 24 tons of fireworks fired for nearly 16 minutes.
Around one million people converged on Times Square, New York, for the annual New Year's Eve celebration. An 11,875lb Waterford crystal ball descended as revellers counted down to 2016 before sharing hugs and their first kisses of the year under a blanket of confetti.
The festivities were policed by nearly 6,000 officers, including members of a counter-terrorism unit.