Landmarks go dark as millions unplug for Earth Hour

The white-shelled roof of the Sydney Opera House fell dark today, one of the first landmarks to turn out the lights in an hour-long gesture to be repeated by millions of people around the world who are calling for a binding pact to cut greenhouse gas emissions.

The fourth annual Earth Hour will see buildings in up to 4,000 cities in more than 120 countries unplug to reduce energy consumption and draw attention to the dangers of climate change, according to organisers.