New Year celebrations have been taking place throughout Europe, with cities on high alert for possible terror attacks.
Russia's President Putin gave New Year address
Thousands of police were on patrol, though the atrocious weather forced the cancellation of some UK celebrations.
Midnight in Moscow (2100 GMT) was greeted by crowds braving thick snow on Red Square but numbers were down on recent years after recent bomb attacks.
In his traditional New Year speech, President Putin sought to raise spirits by reporting a rise in the birth rate.
"It is particularly gratifying that we saw more new citizens of Russia born in the outgoing year than last," he said in a speech broadcast across Russia's 11 time zones.
"That is a good sign. It means that people in this country have more confidence in the future."
Russia has suffered a demographic crisis since the collapse of the Soviet Union.
New Year is still Russia's best-loved holiday, more than a decade after the disappearance of the officially atheist USSR which promoted it as a substitute for Christmas.
About 100,000 people turned out in central London with crowds gathering at Trafalgar Square for midnight, and along the banks of the River Thames to watch a short firework display at the landmark London Eye.
British police had 3,000 officers overseeing the celebrations in the capital, but said they have no intelligence about a specific threat.
A huge outdoor concert planned in Edinburgh was cancelled due to winds and rain.
In Aberdeen, the threat of storm force winds and rain also forced the last-minute cancellation of its street party, disappointing up to 50,000 revellers.
In France, half a million people flocked to Paris's Champs-Elysees to see in 2004.
But Turkey cancelled traditional New Year celebrations in Istanbul following last month's suicide attacks, which left 62 dead.
Many Spanish revellers maintained the tradition of eating a grape on each of the 12 chimes of midnight for good luck.
The country was expected to get through more than 2.25 tonnes of fresh grapes.
The Pope used his New Year's day address to argue for the United Nations to be at the centre of international action.
"More than ever we need a new international order which
draws on the experience and results of the United Nations," the Pope said at a mass in St Peter's Basilica.
"An order which is capable of finding adequate solutions to
today's problems, based on the dignity of human beings, on
integrating all society, on solidarity between rich and poor
countries, on the sharing of resources and the extraordinary
results of scientific and technological progress."