As 2016 draws to a close, revelers around the world are bidding a weary adieu to a year filled with political surprises, prolonged conflicts, deadly attacks at gatherings and deaths of legendary celebrities.
Here's a look at how people are ushering in the new year:
NEW YORK CITY
An estimated 1 million people ushered in the new year in Times Square, screaming and kissing as the glittering crystal ball dropped.
New Year's Eve revelers began to fill Times Square hours before midnight. They braved cold temperatures and strong winds at the Crossroads of the World to greet 2017 amid heavy police protection.
Maria Raimilla, from New Jersey, said 2016 was rough.
"Everything is going to be new," she said at midnight. "I just want to find happiness this year and leave all the bad things behind."
Lori Haan, from Tucson, Arizona, and her husband were on their first trip to New York. She said she's looking forward to what 2017 brings.
"This is a great start to the new year," she said. "We are doing something new and exciting, and I hope that it's a theme for the rest of the year."
Dozens of 20-ton sanitation trucks weighted with an extra 15 tons of sand blocked off streets leading to the celebration zone to avoid the possibility of a truck attack like those in Germany and France in recent months. About 7,000 police officers, along with specially armed counterterrorism units and bomb-sniffing dogs, were on guard.
Mariah Carey headlined in Times Square for "Dick Clark's New Year's Rockin' Eve with Ryan Seacrest" on ABC. She had technical difficulties during her performance and stopped singing, then she paced the stage and urged the audience to belt out the "Emotions" lyrics instead.
"I'm trying to be a good sport here," she said.
Sydney sent up a dazzling tribute to 2016's fallen icons with a New Year's Eve fireworks display honoring the late singer David Bowie and late actor Gene Wilder, becoming the first major city to bid a bittersweet adieu to a turbulent year.
The glittering display over Sydney's harbor and bridge featured Saturn- and star-shaped fireworks set to "Space Oddity," the classic song by Bowie, among the seemingly endless parade of beloved entertainers who died in 2016.
Wilder was honored as the bridge lit up in a rainbow of colors while a song from his film "Willy Wonka and the Chocolate Factory" played.
New Year's celebrations turned deadly when an armed assailant believed to have been dressed as Santa Claus opened fire at a nightclub in Istanbul, killing dozens of people.
Istanbul's governor said at least 39 people were killed and about 70 others were wounded.
Security measures had been heightened in major Turkish cities, with police barring traffic leading up to key squares in Istanbul and the capital, Ankara. In Istanbul, 17,000 police officers were on duty, some camouflaged as street vendors.
Ankara and Istanbul have been targeted by several attacks in 2016 carried out by the Islamic State group or Kurdish rebels, killing more than 180 people.
Neslihan Dogruol, a restaurant owner in a chic Istanbul neighborhood, said she hopes for peace in 2017 following a year filled with "unrest and death."
"2016 affected everyone badly," she said.
More than 2 million people have welcomed 2017 at Rio de Janeiro's Copacabana beach.
Twelve minutes of fireworks amazed many of the more than 860,000 tourists who traveled to Rio for the party.
The event was more modest than last year due to the city's recession. Still, tourists and Brazilians enjoyed a festival of sounds, including two sets of drums from popular samba schools.
A decked-out bride and groom walking to a chapel and photo-happy tourists from halfway around the world were among the estimated 300,000 visitors turning out to celebrate the new year Las Vegas style.
The city's celebration features some of the biggest names in music headlining nightclubs and a fireworks show launching from the tops of half a dozen high-rise casinos.
Local police joined forces with the National Guard, the Secret Service and FBI agents to protect Sin City on one of its biggest nights of the year.
In Berlin the mood was more somber than celebratory.
"I don't like the way politics is going," Daniel Brandt said. "Fears are being fanned, and people are so angry with each other."
The tone of public debate in Germany has become shriller over the past two years with the influx of hundreds of thousands of migrants.
Walking by the Reichstag, Germany's Parliament building, Hamed Noori said 2016 had been a good year.
"I came to Germany from Afghanistan," he said. "Life is better here."
Nicole Durand-Nusser, originally from France but living in Berlin for almost 50 years, said 2016 had been a difficult year: "Brexit, Trump, Erdogan — it's all getting worse."
Later, police said they arrested a man who shouted "bomb, bomb, bomb" at Berlin's massive open-air New Year's party.
President Vladimir Putin invoked a bit of seasonal enchantment in his New Year's Eve remarks to the nation.
"Each of us may become something of a magician on the night of the New Year," Putin said in a short televised address broadcast in the closing minutes of 2016 in each of Russia's 11 time zones. "To do this we simply need to treat our parents with love and gratitude, take care of our children and families, respect our colleagues at work, nurture our friendships, defend truth and justice, be merciful and help those who are in need of support. This is the whole secret."
A beefed-up security presence throughout London and Britain's other major cities did nothing to squelch raucous New Year celebrations highlighted by a breathtaking fireworks display over the River Thames that began just after the Big Ben tower chimed midnight.
Police had added overt and covert personnel to patrol crowded areas, and some barriers were put in place to prevent vehicle attacks.
Britain had a tumultuous year, with a June vote to leave the European Union followed by the resignation of the prime minister, but Warren Male and Natasha Lewis said they looked back on 2016 with fondness.
"Because we've been together," Lewis said.
Tourists and French revelers swarmed along Paris' illuminated Champs Elysees Avenue on a frosty night, admiring the laser display from the Arc de Triomphe and lines of trees sparkling with lights.
"It's so magical to be here in Paris, on what people say is the world's most beautiful avenue," said Maureen O'Reilly, a visitor from Belfast, Northern Ireland.
Some people were happy to say goodbye to 2016.
"It's been such a horrible year, with all these (entertainment celebrity) deaths, Syria, Brexit and Trump. I say: good riddance," said Karine Dublot, from Lyon.
Pope Francis has called on the faithful to help young people find a place in society, noting the paradox of "a culture that idolizes youth" but has made no place for the young.
Francis said during vespers marking New Year's Eve that young people have been "pushed to the margins of public life, forcing them to migrate or to beg for jobs that no longer exist, or fail to promise them a future."
Temple bells echoed at midnight as families gather around noodles and revelers flock to shrines for the biggest holiday in Japan.
Kami Miyamoto, an economics student at Meiji University in Tokyo, traveled home in Hakusan, Ishikawa prefecture, for the holiday.
Miyamoto's mother was preparing soba noodles, a standard New Year's Eve dish in Japan, except in their home it will be filled with green onions and shrimp. As the new year rolls in, the entire family, including her younger brother and sister, will drive to a nearby shrine, which, like temples all over Japan, will be filled with those praying for good fortune in the Year of the Rooster, according to the Chinese zodiac.
Residents in Beijing and Shanghai, China's two largest cities, passed New Year's Eve quietly in a relative state of security lockdown, according to Chinese media reports citing police.
The Bund waterfront in Shanghai had no celebrations, authorities announced this week, while the sale, use and transportation of fireworks in central Shanghai will be prohibited.
Large buildings that often display light shows also stayed dark. More than 30 people died two years ago in a deadly stampede on Shanghai's waterfront, where 300,000 people had gathered to watch a planned light show.
Chinese President Xi Jinping said in his New Year's Eve address his government will continue to focus on alleviating poverty at home and resolutely defending China's territorial rights.
Hundreds of thousands of South Koreans ushered in the new year with a massive protest demanding the resignation of disgraced President Park Geun-hye. It was the 10th straight weekend of protests that led to Park's impeachment on Dec. 9 over a corruption scandal.
The evening rally was planned to overlap with Seoul's traditional bell-tolling ceremony at the Bosinkgak pavilion at midnight, which was also expected to be a political statement against Park.
The city's mayor, Park Won-soon, invited as guests a man whose teenage son was among more than 300 people who died during a 2014 ferry sinking and a woman who was forced into sexual slavery by Japan's World War II military.
Park Geun-hye came under heavy criticism over the way her government handled the ferry disaster.
For most people in India, New Year's Eve is a time for family. In New Delhi and many other cities, newspapers are full of big advertisements for lavish parties at upscale hotels and restaurants. The big draws at the hotel parties are song and dance performances from Bollywood and television stars.
The western city of Mumbai was to host big street parties with thousands of people at the iconic Gateway of India, a colonial-era structure on the waterfront overlooking the Arabian Sea.
And there was talk about money — India's recent devaluing of its currency in an apparent effort to cut graft and tax evasion.
The Philippines' notorious tradition of dangerous New Year's Eve celebrations persisted after President Rodrigo Duterte delayed to next year his ban on the use of powerful firecrackers, often worsened by celebratory gunfire.
Powerful firecrackers and gunfire have maimed hundreds of people and killed some each year across the Philippines despite government crackdowns, an annual government scare campaign and efforts by officials to set up centralized fireworks displays, like on Saturday night.
New Year's is the biggest party of the year in Romania, and thousands of people flocked to the mountains to ski, hike and celebrate, some in the mood for fun, others anxious about global challenges in 2017.
Former Finance Minister Daniel Daianu, traveling to the mountain town of Sinaia, said Western governments should pay closer attention to the public mood.
"People are frustrated, people are resentful and people react," he said. "Unless governments pay attention to fairness and fair play, we could see some very unpleasant surprises."
Early Saturday, young Romanians roamed streets and trains, wearing peasant costumes and singing traditional songs about goats, a New Year symbol, while waving wands made of dried flowers.
UNITED ARAB EMIRATES
In Dubai, hundreds of thousands of people watched fireworks shoot from the sides of the world's tallest building, the Burj Khalifa.
There was no repeat of the chaos of last year, when police say faulty wiring sparked a fire several hours before midnight at a skyscraper nearby.
Finland has kicked off celebrations for 100 years of independence from Russia.
Tens of thousands of people gathered in Helsinki for a concert and a huge fireworks display to celebrate the beginning of festivities marking its independence.
Throughout 2017 there will be hundreds of events in the Nordic nation of 5.5 million, from films, dance parties and environment-related events to concerts and activities linked to its renowned sauna tradition.
Celebrations will culminate on Dec. 6, the day Finnish Parliament declared independence in 1917 amid the turmoil of the Russian Revolution.
Finland shares an 800-mile border with Russia. Russian President Vladimir Putin on Friday congratulated Finland for its centenary in a phone conversation with Finnish President Sauli Niinisto.
Thousands of people in Mexico City are expected to turn out for a New Year's Eve concert at the Monument to Independence, better known as The Angel.
Workers spent several days setting up a stage and a booming sound system along a stretch of the central Paseo de la Reforma boulevard. Streets were blocked off in the area, and 2,000 police officers were on hand for security.
The lineup includes a mix of Latin pop and balladeer Jorge "Coque" Muniz, with cumbia band Los Angeles Azules heating things up after a midnight fireworks show.