In last year's Earth Hour, 4,000 cities and 1,000 landmarks turned off their lights beginning at 8:30 p.m., including the Eiffel Tower in Paris, Christ the Redeemer in Rio de Janeiro; New York's Empire State Building, Rome's Colosseum, San Francisco's Golden Gate Bridge, the Sydney Opera and the Las Vegas Strip.
The National Grid Corp. of the Philippines told The Philippine Star metro Manila and surrounding provinces were blacked out for 3 hours when a line was tripped at a substation around 2 p.m.
The Philippines led the world in Earth Hour participation in the last two years.
Downtown Sydney cut its energy consumption by 12 percent Saturday, the Sydney Morning Herald reported.
Scotland became the first country to secure support from all its cities and local authorities, the World Wildlife Fund told the BBC. Edinburgh Castle, the Scottish Parliament building and many other landmarks will take part.
Dermot O'Gorman, chief of the World Wildlife Fund Australia, said Earth Hour "has evolved … from a small idea to something which is now embraced by 131 countries and hundreds of millions of people.''