International landmarks went dark Saturday as lights were switched off in thousands of cities around the world for "Earth Hour," a global call for action on climate change. Hundreds of millions of people were asked to turn off non-essential lights at landmarks, businesses and homes from 8:30 p.m. to 9:30 p.m. local time in each of the world's time zones.
Brazilians celebrated the start of Earth Hour Saturday with a ceremony in Rio de Janeiro in which officials turned off a giant light switch to darken major landmarks for 60 minutes.
It was the fourth annual Earth Hour to be organized by the World Wildlife Fund (WWF), which said global participation in this year's event jumped to 126 countries from 88 nations last year. The goal was the same as before, to raise public awareness about the threat of climate change.
Brazil's Environment Minister Carlos Minc says the more people are involved, the more politicians will take notice.
Minc says consumer actions can make companies change and such actions already have prompted thousands of businesses around the world to take part in Earth Hour. He says now the government must follow through by changing its habits.
Brazilian authorities did their part by turning off the lights at some of Rio's greatest icons, including Copacabana beach and the Statue of Christ the Redeemer.
In the United States, New York's Empire State Building went dark, kicking off a nationwide observance of Earth Hour that spread to all 50 states and Washington DC.
When the clock struck 8:30 p.m. in the western United States, it was the turn of Las Vegas to darken some of the buildings along its famed strip of hotels and casinos.
In Europe, Paris was one of many major cities to join the global blackout, switching off lights at its Eiffel Tower and Arc de Triomphe.
Jim Leape of the World Wildlife Fund was in Beijing to see the lights go off at the Chinese capital's Forbidden City. He says Earth Hour produces real savings in energy usage, but its impact on global politics is even more important.
"In the end this is an opportunity for people everywhere who are concerned about climate change to express that concern in a powerful way," said Leape. "And I think it is clear that it sends a very strong signal to decision makers that there is a political demand for action and that it is time for them to come to grips with this problem."
Hong Kong was taking part in Earth Hour for a second year in a row, shutting off the lights of skyscrapers on both sides of Victoria Harbor.
Local housewife Karen Chu says the event is an opportunity for parents to teach an important lesson to their children.
Chu says children must learn that electricity should be turned off when it is no longer needed. She says that lesson will enable parents to deliver a good message to the next generation.