Dazzling fireworks lit up Australia's Sydney Harbour, communist Vietnam held a rare, Western-style countdown to the new year, and Japanese revellers released balloons carrying notes with people's hopes and dreams as the world ushered in 2011.
In Europe, Greeks, Irish and Spaniards partied through the night to help put a year of economic woe behind them.
And in New York, nearly a million New Year's Eve revellers crammed into Times Square to watch the midnight ball drop, just days after the city got clobbered by a blizzard.
As rain clouds cleared, thousands of people, many sporting large, brightly coloured wigs, gathered in Madrid's central Puerta del Sol square to take part in Las Uvas, or The Grapes, a tradition in which people eat a grape for each of the 12 chimes of midnight.
Chewing and swallowing the grapes to each tolling of the bell is supposed to bring good luck, while cheating is frowned on and revellers believe it brings misfortune. "I'm here to make my wishes for the New Year. If you eat the grapes your wishes will come true," said beautician Anita Vargas, 22.
2010 was a grim year for the European Union, with Greece and Ireland needing bailouts and countries such as Spain and Portugal finding themselves in financial trouble as well. Athens, Paris and London have all seen unrest in the streets. "Before, we used to go out, celebrate in a restaurant, but the last two years we have had to stay at home," said Madrid florist Ernestina Blasco, 48. She said her husband, a construction worker, is out of work.
In Greece, thousands spent the last day of 2010 standing in line at tax offices to pay their road tax or sign up for tax amnesty. "We can see that the quality of life is being degraded every day. What can I say? I don't see the light at the end of the tunnel," said Giorgos Karantzos of Athens.
New Zealanders and South Pacific island nations were among the first to celebrate at midnight. In New Zealand's Auckland, explosions of red, gold and white burst over the Sky Tower, while tens of thousands danced and sang in the streets below. In Christchurch, party-goers shrugged off a minor 3.3 earthquake that struck just before 10 p.m.
Multi-coloured starbusts and gigantic sparklers lit the midnight sky over Sydney Harbour in a pyrotechnics show witnessed by 1.5 million spectators. Also, hundreds of thousands of people gathered along Hong Kong's Victoria Harbour to watch fireworks explode from the roofs of 10 of the city's most famous buildings.
Meanwhile on New Year's Day some 10,000 people plunged into the icy waters of the North Sea at Scheveningen Beach to take part in the traditional swim.