PARIS -- Fireworks exploded over Sydney's famous bridge and the Eiffel Tower prepared for its own colored-light spectacle as the world celebrated a New Year that many hope will be more prosperous and peaceful than 2009.
Revelers across the globe at least temporarily shelved worries about their future prospects to bid farewell to the first decade of the 21st century.
The financial downturn hit hard in 2009, sending many industrial economies into recession, tossing millions out of work and out of their homes, as foreclosures rose dramatically in some countries.
Germany's leader warned her people that the start of the new decade won't herald immediate relief from the global economic ills. South Africa's president was more ebullient, saying the World Cup is set to make 2010 the country's most important year since the end of apartheid in 1994.
Other leaders focused on the positive aspects of 2009.
Australian Prime Minister Kevin Rudd said 2009 had been an extraordinary year for the world -- citing the inauguration of the United States' first black president and international attempts to grapple with climate change and the global financial crisis.
''The great message from 2009 is that because we've been all in this together, we've all worked together,'' Rudd said in a New Year's message.
Australia got the festivities rolling Thursday, with Sydney draping its skies with explosive bursts of crimson, purple and blue to the delight of more than 1 million New Year revelers.
The environmental concerns that accompanied the U.N. summit in Copenhagen were on the minds of some as the year ended.
Venice revelers were set to ring in the New Year with wet feet as high tide was to peak just before midnight to flood low-lying parts of the city -- including the St. Mark's Square.
In winter, tourists checking into Venice hotels are regularly asked their shoe sizes so they can be fitted with boots to face the lagoon city's exceptionally high tides.
The last year also offered its reminders of the decade's fight against terrorism, wars in Iraq and Afghanistan, and more recently, rising militant violence in Pakistan.
The American Embassy in Indonesia warned of a possible terrorist attack on the resort island of Bali on New Year's Eve, citing information from the island's governor -- though local security officials said Thursday they were unaware of a threat.
More than 8,000 police and soldiers were deployed for extra security in and around Paris. The Eiffel Tower was decked out for its 120th anniversary year with hundreds of multicolored lights for a show that's more energy-saving than its usual sparkling-light display.
Despite forecasts for below-freezing temperatures, thousands were expected to gather on the banks of the River Thames in London for fireworks after Big Ben strikes midnight.
''(2009 was) like shock therapy, where people really change when something bad happens to them,'' said accountant Conrad Jordaan, 35.