Every year for a century, a five metre light-studded crystal ball has descended above revellers in New York’s Times Square to officially mark the beginning of the new year.
This year, singers Lady Gaga and Justin Bieber helped a estimated one million people kick off 2012 with New York mayor Michael Bloomberg looking on.
Some New York revellers, wearing party hats and ‘2012’ glasses, began camping out on Saturday to get the best places.
For security reasons, police closed off streets around Times Square and prohibited celebrants from bringing alcohol, backpacks, large bags or packages into the area.
In Brazil, two million people partied on Rio de Janeiro’s Copacabana Beach as an estimated 24 tons of fireworks were let off, launched from 11 boats.
Light rain fell during the celebration, but it did not dampen the mood of the revellers as they watched the 16-minute display.
Immediately after the countdown, the sky was covered with an intense green light. Organisers said the colour was chosen to highlight a large UN environment summit taking place in Rio in June.
Following the fireworks, the crowd enjoyed a series of concerts on four stages spread throughout the Copacabana beach area. Performers included international DJ David Guetta and Brazilian artist Beth Carvalho and Samba school Beija-flor.
Over 1,500 police officers were on hand to make sure the celebrations were safe.