Crowds of Australians have welcomed in the new year with a huge fireworks extravaganza at Sydney's landmark waterfront Opera House.
Australia is among the first countries to celebrate the arrival of 2006 as people around much of the rest of the world await their chance to join the festivities.
Celebrations with fireworks, music and much fanfare are planned for major Asian cities, followed by events across South Asia, the Middle East, Africa, Europe and Latin America.
The United States is among the last to usher in the new year. A huge celebration is planned for New York where revelers will say goodbye to 2005 in Times Square.
President Bush has issued a message of reflection for the outgoing year, and of hope for 2006.