Millions staged midnight parties at icon landmarks around the world to see in 2008 but bomb attacks and security fears quickly darkened New Year festivities.
More than one million people lined Sydney harbour for fireworks which set off the global party. Hundreds of thousands packed Hong Kong streets and historic European venues such as the Brandenburg Gate in Berlin and the Champs Elysees in Paris.
An estimated 700,000 people were out on the damp London streets and crammed on riverbanks to watch the 10-minute fireworks display on the Thames, which focused on the giant London Eye observation wheel, police said.
"It's amazing to be in one of the world's most vibrant cities on a night like this, when the whole of London is just out having fun," said Londoner James O'Shea (32), who arrived three hours early to secure a good spot.
Meanwhile in Edinburgh, around 95,000 people packed into Princes Street, the Scottish capital's main thoroughfare, for the Hogmanay street party, organisers said.
But bombs planted by suspected separatist rebels at discos and other entertainment centres rocked Thailand's troubled south as revelry was at its peak, killing one person and injuring dozens, police said.
Bombs in the Thai capital at the last New Year's party killed three people. In Pakistan's biggest city, Karachi, police stopped thousands from attending a traditional gathering on a beach overlooking the Arabian Sea amid security fears after the assassination of opposition leader Benazir Bhutto.
Belgian authorities cancelled a traditional fireworks show in Brussels as the country went on maximum alert over possible terror threats.
French authorities put 13,000 police on the streets of Paris and its troubled suburbs to deter any repeat of riots last month. Youths still hurled cans at the car of Interior Minister Michele Alliot-Marie as she toured potential trouble spots.
But an estimated 400,000 French and foreign visitors still turned the Champs Elysees into a mass of car-honking festivities.
Even more people -- around one million according to police -- packed streets around the Brandenburg Gate in what German media billed as the world's biggest New Year's party.
The giant steel archway of the Sydney Harbour Bridge was again the centrepiece of the traditional display in Australia's main city, with a giant neon hourglass illustrating the theme of time passing.
Thousands in Hong Kong ignored unusually chilly temperatures to see the fireworks in Victoria Harbour. In the northern Chinese city of Harbin, tourists strolled through a display of ice structures and some toasted the New Year in a bar made from ice blocks.
In Japan, thousands of people gathered at the Yasukuni shrine and other prayer sites to throw coins as midnight struck. Each addressed a small prayer to the country's ancestral gods by twice clapping their hands under a clear winter sky.
In Iraq, crowds surged into the streets of strife-torn Baghdad, shooting firecrackers and weapons and dancing in a rare moment of freedom from daily violence that has recently eased encouraging inhabitants to be more daring.