Exuberant firework displays and huge street parties have been marking the start of 2006 across the world.
From Sydney to London, Moscow to New York, crowds of people have been cheering in the New Year.
In Brazil, Rio de Janeiro held its biggest fireworks display, while revellers ignored bad weather to pack into Times Square in New York.
The US city of New Orleans said goodbye to 2005 with a jazz funeral procession for the victims of Hurricane Katrina.
Four months after the devastation which killed more than 1,000 people, the southern city welcomed 2006 with concerts and music, putting on a show that officials hope will help draw back the tourists.
For many Asian cities, the New Year celebrations were their first such event for two years, after the Indian Ocean tsunami caused celebrations for 2005 to be cancelled.
In the Australian city of Sydney, police deployed in strength to prevent a repetition of the racial violence seen earlier this month.
France put thousands of extra police officers on duty to prevent the urban unrest seen in towns and cities in the latter part of 2005.
Half-a-million people thronged the streets around the Eiffel Tower and in the Champs-Elysees in Paris.
No serious outbreaks of unrest were reported but police said 425 vehicles were torched overnight, up from 333 last year.
In Moscow, revellers welcomed the New Year in Red Square without their favourite tipple, after the authorities banned alcohol from the historic plaza.
Hundreds of thousands of people in Germany celebrated in chilly temperatures around Berlin's Brandenburg Gate, while the Spanish capital Madrid put on a huge street party.
In London, revellers defied a strike on the city's underground system to enjoy a massive firework display along the banks of the River Thames.
Thousands also gathered in Trafalgar Square and outside the Houses of Parliament, to hear Big Ben chime midnight.
In New York's Times Square, fireworks burst above the packed crowds, in an event that included tributes to the victims of Hurricane Katrina and the rescue workers involved.
The US city of Boston also honoured New Orleans with a Mardi Gras theme that included a carnival parade and jazz bands.
But on the US west coast, Los Angeles had to cancel an outdoor music concert for 20,000 people as a powerful storm moved through the region.
US troops in Baghdad, Iraq, were treated to a special show from entertainers at Camp Victory.