Millions of people have gathered in cities and towns across the planet to remember 2005 and usher in the New Year.
Huge crowds braved tight security and cold, rainy weather for celebrations at New York's Times Square.
The arrival of 2006 was also cheered in New Orleans, the historic Gulf Coast city devastated by Hurricane Katrina last August. Thousands of revelers packed the French Quarter to listen to music by Arlo Guthrie and bid good riddance to a year the city was not likely to forget.
In New York, security was a main concern amid the festive atmosphere, although Mayor Michael Bloomberg had said there were no specific threats against the city. Police officers led bomb-sniffing dogs throughout the party zone, while biochemical hazard teams and decontamination centers were on standby in case of attack.
Snipers were deployed on rooftops, while helicopters circled the area and police patrolled the city's waterways on boats.
Hundreds of thousands of Russians thronged for a massive party in Moscow's Red Squre, albeit without their beloved vodka, which had been banned as a security measure.
France put thousands of extra police officers on duty in an effort to prevent the urban unrest seen in towns and cities this autumn. An estimated 500,000 people thronged the streets around the Eiffel Tower and in the Champs-Elysees in Paris.
In London, Tube workers began a 24-hour strike just in time to cripple the transport system on a night when thousands of revelers were planning to celebrate New Year.
Huge crowds also gathered in Berlin, Dublin and other European cities.
Last night, Australia's traditional fireworks spectacular in Sydney drew more than one million people to the harbour-front area. Security was tight for the celebration, with close to 1,700 police patrolling the streets and beaches.
In Beijing, bells and drums sounded 108 times at midnight in a Buddhist ceremony aimed at ending global conflict.
The arrival of 2006 was also celebrated in the Japanese capital, Tokyo and in Hong Kong a massive light and sound show saw fireworks explode from 20 buildings around Victoria Harbor.
Generally jubilant celebrations planned across Asia were in sharp contrast with last year, when the devastation of the Indian Ocean tsunami led many countries and individuals to cancel festivities.