Fireworks illuminated skies over Paris Rio and Sydney to celebrate the entry to 2024, while in Israel, Gaza and Ukraine, rockets and strikes marked the year's earliest hours.
Much of the world's population -- now more than eight billion -- is hoping to shake off high living costs and global tumult in 2024, which will bring elections concerning half the world's population and the Paris Olympics.
But with the new year barely started there were already ominous signs: at the stroke of midnight in Gaza a barrage of rockets was fired towards Israel - a twisted reflection of the fireworks lighting up night skies elsewhere around the world.
In New York City, thousands of visitors lined up for a chance to see the annual dropping of a giant illuminated ball in Times Square.
Nearby stallholders hawked vuvuzelas and 2024-branded hats as police fanned out across central Manhattan, towing suspicious cars, closing roads and manning a ring of steel screening would-be revelers.
Hours earlier, more than a million partygoers had packed in around the harbor in Sydney, the self-proclaimed "New Year's capital of the world," to watch eight tonnes of fireworks.
Pyrotechnics also illuminated the skies in Auckland, Hong Kong, Manila and Jakarta. Nudist bathers wearing Santa hats waded into the mild waters of southern France, while revelers danced in the streets in Greece's Thessaloniki.
In Denmark, popular Queen Margrethe II, Europe's longest-serving monarch, chose her New Year's Eve address to announce her coming abdication.
The 83-year-old monarch will step down in favor of her son, Crown Prince Frederik, after 52 years on the throne.
The last 12 months brought "Barbenheimer" to the box office, a proliferation of human-seeming artificial intelligence tools, and a world- first whole-eye transplant.
India outgrew China as the world's most populous country, and then became the first nation to land an unmanned craft on the Moon's south pole.
It was also the hottest year since records began in 1880, with a spate of climate-fuelled disasters striking across the world.
Fans bade adieu to "Queen of Rock 'n' Roll" Tina Turner, "Friends" actor Matthew Perry, hell-raising Anglo-Irish songsmith Shane MacGowan, and master dystopian novelist Cormac McCarthy. - Rebuilding -
2023 will be remembered for war in the Middle East, after Hamas's unprecedented October 7 raids on southern Israel and Israel's ferocious reprisals on Gaza.
The United Nations estimates that almost two million Gazans have been displaced since Israel's siege began, or about 85 percent of the peacetime population.
With once-bustling Gaza City neighborhoods reduced to rubble, there were few places left to mark the new year -- and fewer loved ones to celebrate with.
"It was a black year full of tragedies," said 37-year-old Abed Akkawi, who fled the city with his wife and three children to a UN shelter in Rafah, southern Gaza.