The celebrations are not done for millions of people welcoming in 2011.
Hours after revelers stayed up late to greet the new year with fireworks and music in their respective countries, many more are lining parade routes or preparing to take part in other festivities.
Despite cold and rainy weather early Saturday, thousands of Americans gathered in Pasadena, in the western U.S. state of California for the annual Rose Parade.
Organizers expect more than 700,000 people to attend the 122-year-old parade, part of the city's annual Tournament of Roses.
This year's parade features 47 parade floats and 22 marching bands. It precedes the Rose Bowl, a much-watched game of American football.
In London, people celebrated Saturday with the city's 25th annual New Year's Day parade. That parade featured more than 8,000 musicians and performers.
Officials said they expected half-a-million people to line the parade route.
Some of the biggest New Year celebrations took place overnight.
About one million revelers cheered in New York's Times Square as a giant Waterford Crystal ball descended during the countdown to the new year. Fireworks lit up the New York skyline and a loud chant of "Happy New Year" filled the air.
Celebrations in South American countries were highlighted by an impressive fireworks display in Buenos Aires, Argentina.
London hosted one of Europe's biggest celebrations, on the banks of London's River Thames. Around a quarter of a million people gathered to watch fireworks as the famous Big Ben at Parliament chimed in the new year.
Revelers across Europe, Africa, Asia and the Pacific Islands welcomed 2011 hours ago. The tiny Pacific island nation of Kiribati was the first to ring in 2011.