Australia's largest city Sydney will put on its biggest-ever fireworks display to welcome the New Year and kick off a wave of celebrations for billions around the world.
A record amount of pyrotechnics, as well as new fireworks effects and colours, will light up the harbour city's skyline for 12 minutes and dazzle the more than 1.5 million spectators expected to crowd foreshores and parks.
"I'm sure we'll delight in seeing our beautiful harbour lit up like never before," Sydney Lord Mayor Clover Moore said.
To mark the international year of indigenous languages in 2019, the harbour will host a ceremony celebrating the Aboriginal heritage that includes animations projected onto the Sydney Harbour Bridge's pylons. The party atmosphere will sweep across major cities in Asia, Europe, Africa, and the Americas as the clock ticks past midnight.
A strong police presence has become a key element of the festivities, to protect crowds that could be targeted in terror and vehicle attacks.
Hong Kong: Glittering fireworks will be sent skyward from five barges floating in Victoria Harbour in a 10-minute display watching by 300,000 people on the foreshore.
Tokyo: Japanese will flock to temples to ring in the New Year, while US boxer Floyd Mayweather Jr will take on local kickboxer Tenshin Nasukawa in a bout staged outside Tokyo.
Moscow: Concerts and light shows will be held across the city's parks and more than 1,000 ice rinks have been opened for merrymakers.
Paris: A fireworks display and sound and light show under the theme "fraternity" is set to go ahead on the Champs-Elysees despite plans for further "yellow vest" anti-government protests at the famed avenue.
Berlin: Music lovers will party at a concert at the Brandenburg Gate, but a popular German tradition of setting off fireworks to mark the occasion has been banned in some other cities over safety concerns.
London: Britain's capital will usher in the New Year by celebrating its relationship with Europe amid turmoil over the Brexit referendum vote to leave the union, with the fireworks display at the London Eye to feature music from the continent's artists.
Edinburgh: The Scottish capital's traditional Hogmanay celebrations will also take on a pro-European theme ahead of the year in which Britain is due to exit the EU.
As the world parties, many will also look forward to 2019 and wonder whether the turmoil witnessed during the previous year will spill over into the next.