Crowds will marvel at fireworks and toast champagne to greet 2025 on Tuesday, waving goodbye to a year that brought Olympic glory, a dramatic Donald Trump return, and turmoil in the Middle East and Ukraine.

It is all but certain 2024 will go down as the hottest year on record, climate-fueled disasters wreaking havoc from the plains of Europe to the Kathmandu Valley.

As New Year's Eve parties kicked into gear along Australia's picturesque Sydney Harbour on Tuesday afternoon, many revelers were relieved to see the past 12 months in the rearview mirror.

"Obviously there's a lot of war and disruption going on in various places," insurance worker Stuart Edwards, 32, told AFP as early crowds swelled on Sydney's waterfront. "It would be nice for the world if it all sort of fixed itself, sorted itself out."

The self-proclaimed "New Year's capital of the world" will spray nine tons of fireworks from its famed Opera House and Harbour Bridge at midnight.

More than a million spectators are expected to pack the city's foreshore to catch a glimpse of the pyrotechnics.

"Just to see all the beautiful colors and enjoy being in this situation with so many people in wonderful Australia," said 71-year-old retired nurse Ruth Rowse.

Taylor Swift brought the curtain down on her Eras tour this year, pygmy hippo Moo Deng went viral, and 16-year-old soccer prodigy Lamine Yamal helped Spain conquer the Euros.

The Paris Olympics united the world for a brief few weeks in July and August.

Athletes swam in the Seine, raced in the shadows of the Eiffel Tower, and rode horses across the manicured lawns outside the Palace of Versailles.

It was a global year of elections, with countless millions going to the polls across more than 60 countries.

Vladimir Putin prevailed in a Russian ballot widely dismissed as a sham, while a student uprising in Bangladesh toppled the reigning prime minister.

However, no vote was as closely watched as the November 5 contest that will soon see Donald Trump back in the White House.

From Mexico to the Middle East, Trump's looming return as commander-in-chief is already making waves.

The president-elect has threatened to pile economic pain on China and boasted of his ability to halt the Ukraine war within "24 hours".

Turmoil rippled across the Middle East as Bashar al-Assad fled Syria, Israel marched into southern Lebanon, and doctored electronics exploded in a wave of assassinations targeting Hezbollah.

Civilians grew weary of the grinding war in Gaza, where dwindling stocks of food, shelter and medicine made a humanitarian crisis even bleaker.

"The year 2024 was the most difficult year," Wafaa Hajjaj told AFP from Deir el-Balah, where masses of displaced residents now cram into crowded tents.

"I lost many loved ones, including my father and close friends, starting from the beginning of the year," she said. "May security and safety return, and may the war finally come to an end."

There was hope and trepidation as the new year approached in Syria, which is still reeling after Islamist rebels toppled longtime ruler Assad.

"We were hesitant to go out this year because of the security situation, but we decided to overcome our fears and not change our habits," lawyer Maram Ayoub, 34, told AFP from the capital Damascus.

Russia's invasion of Ukraine inches toward its grim three-year anniversary in February.

Outgunned on its eastern flank, Ukraine must now contend with a Trump administration seemingly intent on winding back crucial military aid.

On the streets of Kyiv, teacher Kateryna Chemeryz wanted "peace to finally be obtained for Ukraine" and for "people to stop dying".

With AI advances on the horizon and rampant inflation tipped to slow, there is still plenty to look forward to in 2025.

Britpop bad boys Oasis will make a long-awaited reunion, while K-pop megastars BTS return to the stage after military service in South Korea.

Soccer aficionados will be treated to a revamped 32-team Club World Cup hosted in the United States.

And some 400 million pilgrims are expected at the spectacular Kumbh Mela festival on India's sacred riverbanks -- billed as the largest gathering of humanity on the planet.

The UK weather service has already forecast sweltering global temperatures for 2025, suggesting it is likely to rank among the hottest years recorded.

But with electric vehicle sales growing and renewable energy on the rise, there is a shred of hope that glacial progress on climate change may finally gain momentum.