Lights across 7,000 cities in 172 countries will be switched off for an hour at 8.30 pm on Saturday to mark the 10th anniversary of Earth Hour. The gesture has been planned to highlight climate change and the need to save a few megawatts of electricity, reported Reuters.

Among the famous buildings taking part are the Burj Khalifa in Dubai, London’s Big Ben, the Eiffel Tower, Sydney’s Opera House, Istanbul’s Blue Mosque, Moscow’s Kremlin and the Pyramids of Egypt. India, too, is taking part in the event.

The World Wildlife Fund had initiated this step in Australia way back in 2007. It is now considered the world’s largest movement for the environment. Ravi Singh, the secretary general and chief executive officer of WWF-India, told The Hindu the Earth Hour encourages people to take positive action against climate change.