And here from the Associated Press is a round-up of what's going on tonight, across the globe.
As Russians raised toasts to celebrate across the country's 11 time zones, President Vladimir Putin stressed the need to rely on internal resources to improve living standards.
In a televised address just before midnight, Putin said that "we can achieve positive results only through our own efforts and well-coordinated teamwork."
Raising life quality remains the top priority, he said, adding that it's necessary to tap domestic resources to achieve the goal as "there wasn't and there won't be anyone to help."
The statement sounded like an oblique reference to continuing Russia-West tensions and Western sanctions.
The nation's festive mood was marred by the collapse of an apartment building Monday in Magnitogorsk that killed at least four. Putin visited the city to oversee rescue efforts.
While many celebrate New Year's Eve with fireworks, hundreds of Thais traveled to Takien Temple in a suburb of Bangkok to lie inside coffins for traditional funeral rituals.
Participants believe the ceremony — symbolizing death and rebirth — helps rid them of bad luck and allows them to be born again for a fresh start in the new year.
They held flowers and incense in their hands as monks covered them with pink sheets and chanted prayers for the dead.
"It wasn't scary or anything. It is our belief that it will help us get rid of bad luck and bring good fortune to our life," said Busaba Yookong, who came to the temple with her family.
Dozens of people have been injured ahead of New Year's Eve, when many across the Philippines set off powerful firecrackers in one of Asia's most violent celebrations despite a government scare campaign and threats of arrests.
The Department of Health said it has recorded more than 50 firecracker injuries in the past 10 days, which is expected to increase overnight when Filipinos usher in 2019.
Officials have urged centralized fireworks displays to discourage wild and sometimes fatal merrymaking.
The notorious tradition, worsened by celebratory gunfire that turned deadly, stems from a Chinese-influenced belief that noise drives away evil and misfortune.
Earlier Monday, suspected Muslim militants remotely detonated a bomb near the entrance of a mall in Cotabato as people did last-minute shopping ahead of celebrations, killing at least two and wounding nearly 30, officials said.
Japanese usually welcome the New Year with a visit to a temple or shrine, but some 30,000 people at Saitama Super Arena did it with Floyd Mayweather.
The American boxer soundly defeated his opponent, Japanese kickboxer Tenshin Nasukawa, in the first round of what was billed as three rounds of entertainment with no official record, meaning both fighters still retain their undefeated tallies.
"I told Tenshin to hold your head up high," Mayweather said of his advice after the bout.
Nasukawa was floored three times in the first round, and although he kept getting up, teetering, his father in the corner threw in the towel.
New Year's Eve isn't celebrated widely in mainland China, where the lunar New Year in February is a more important holiday, but countdown events were held in major cities, and some of the faithful headed to Buddhist temples for bell-ringing and prayers.
Beijing was holding a gala with VIP guests at the main site of the 2008 Summer Olympics. The event looked ahead to the 2022 Winter Games, which also will be held in the Chinese capital.
Outdoor revelers in Beijing had to brave temperatures well below freezing.
Additional police were deployed in parts of Shanghai, where a New Year's Eve stampede in 2014 killed 36 people.
In Hong Kong, festive lights on skyscrapers provided the backdrop for a fireworks, music and light show over Victoria Harbor on a chilly evening.
The Pacific island nation of Kiribati was the first in the world to welcome the new year, greeting 2019 with muted celebrations after spending 2018 on the front line of the battle against climate change.
Kiribati is made up of low-lying atolls along the equator which intersect three time zones, the first of which sees the new year 14 hours before midnight in London.
Much of the nation's land mass, occupied by 110,000 people, is endangered by rising seas that have inundated coastal villages. The rising oceans have turned fresh water sources brackish, imperiling communities and raising doubts the nation will exist at the next New Year.
Former President Anote Tong said the only future for Kiribati may be mass migration.
The new year was welcomed in the capital, Tarawa, with church services and mostly quiet private celebrations.
In Auckland, New Zealand's biggest city, tens of thousands gathered around Sky Tower as fireworks exploded from the top of the 328-meter (1,076-foot) structure.
Across the Southern Hemisphere nation, thousands took to beaches and streets, becoming the first major nation to usher in 2019.
Fireworks boomed and crackled above city centers and harbors.
An estimated million people crowded Sydney Harbor as Australia's largest city rang in the new year with a spectacular, soul-tinged fireworks celebration.
One of the most complex displays in Australia's history included gold, purple and silver fireworks pulsating to the tune of "(You Make Me Feel Like) A Natural Woman," made famous by Aretha Franklin, who died in August. The show used 8.5 tons of fireworks and featured more than 100,000 pyrotechnic effects.
Earlier, a thunderstorm drenched tens of thousands of people as they gathered for the traditional display, creating a show of its own with dozens of lightning strikes.
In Melbourne, 14 tons of fireworks deployed on the ground and on roofs of 22 buildings produced special effects including flying dragons. In Brisbane, people watched as fireworks exploded from five barges moored on the Brisbane River.
After an eventful year that saw three inter-Korean summits and the easing of tensions over North Korea's nuclear program, South Koreans entered 2019 with hopes that the hard-won detente will expand into a stable peace.
Thousands of South Koreans filled the streets of the capital, Seoul, for a traditional bell-tolling ceremony near City Hall. Dignitaries picked to ring the old Bosingak bell at midnight included famous surgeon Lee Guk-jong, who successfully operated on a North Korean soldier who escaped to South Korea in 2017 in a hail of bullets fired by his comrades.
A "peace bell" was tolled at Imjingak, a pavilion near the border with North Korea.
Parisians and tourists gathered on the Champs-Elysees to celebrate New Year's Eve under heavy security.
Anti-government protesters from the "yellow vest" movement have issued calls on social media for "festive" demonstrations on the famous avenue.
Paris police have set up a security perimeter in the area, with bag searches, a ban on alcohol and traffic restrictions. The Interior Ministry said Sunday that the heavy security measures are needed because of a "high terrorist threat" and concerns about "non-declared protests."
President Emmanuel Macron is to give his traditional New Year address to briefly lay out his priorities for 2019, as some "yellow vest" protesters angry over high taxes and his pro-business policies plan to continue their demonstrations in coming weeks.
Before midnight, a light show illustrating the theme of brotherhood is to take place on the Arc de Triomphe monument at the top of the Champs-Elysees.
Snoop Dogg, Sting and Christina Aguilera will welcome 2019 in a packed Times Square along with revelers from around the world who come to see the traditional crystal ball drop.
Spectators began assembling early in the afternoon for the made-for-TV extravaganza.
The celebration will take place under tight security, with partygoers checked for weapons and then herded into pens, ringed by metal barricades, where they wait for the stroke of midnight.