New Year festivities swept across Europe on Thursday with millions of party-goers attending firework displays and street parties.
Revellers braved freezing conditions in London to see the New Year fireworks spectacular on the banks of the River Thames, which engulfed the London Eye in a blaze of colour.
An estimated 400,000 people lined the embankments to catch the 10-minute salvo.
The Scottish capital Edinburgh's traditional Hogmanay knees-up opened a year-long "Homecoming" festival aimed at the country's diaspora.
In Paris, more than half a million people had already thronged on the French capital's famed Champs-Elysees an hour before the bells.
About 100,000 people gathered in Bratislava's main square in Slovakia to celebrate the country becoming the 16th member of the eurozone.
In Prague, the Czech Republic took over the European Union presidency from France at midnight as a top government official illuminated a giant pendulum on a hill above Prague with blue and yellow.
In Venice, some 30,000 welcomed in 2009 with a collective kiss.
Another 100,000 people descended on the Polish capital Warsaw, while in Athens' Syntagma Square - the scene of many violent protests by Greek youth in the last month - the mood was equally upbeat.
But in the northern Greek city of Thessaloniki youths set trash cans on fire in the city centre and lobbed Molotov cocktails at police, who responded with tear gas.
And tragedy struck New Year celebrations when fire ripped through a Bangkok nightclub, killing at least 60 revellers.
Hamas' vow to fight Israel "until the last breath" in Gaza also dampened celebrations among Muslim sympathisers.
Several Arab states cancelled planned celebrations as Palestinians in the Islamist-run Gaza Strip suffered a fifth straight day of Israeli bombardment on Wednesday.
Egypt, Jordan, Dubai and Syria all called off festivities including concerts by renowned Arab singers. Morocco even cancelled state television broadcasts, judging the mood inappropriate, according to Rabat's information minister.
In India, where nuclear-armed tensions with neighbouring Pakistan remain all pervasive, Mumbai was marked by tight security after the trauma of the November terror attacks that left 172 people dead.
The Indian resort state of Goa banned its famous beach parties - a huge draw for foreign tourists - with extra paramilitary troops deployed to ensure security.
Up to 1.5 million Australians and tourists converged on the site surrounding Sydney's world-famous Opera House for the city's biggest-ever fireworks display.
New Zealand staged a dramatic fireworks display from Auckland's Sky Tower two hours earlier and 2009 officially kicked in on Kiritimati, or Christmas Island, in the Pacific Ocean, at 1000 GMT.
The global financial meltdown dampened spirits, with laid-off workers in Japan's Tokyo camping out in the city's Hibiya Park after companies - including leading carmakers - cut tens of thousands of jobs.
China's main festivities will come later in the month with a week-long holiday for the traditional Chinese Lunar New Year celebrations.