Earth Hour is 10 years old

The lights are being switched off around the world at 8:30 p.m. on Saturday evening, to mark the 10th annual Earth Hour, and to draw attention to climate change.

The initiative began in Australia in 2007 as a grass roots gesture by the World Wildlife Fund (WWF) Australia against man-made carbon dioxide emissions linked to a warming planet.

In 2017, it will involve the switching off of electric lights for an hour in 7,000 cities across 172 countries, at 8:30 p.m. local time, with the aim of highlighting the need to act on climate change, and saving a few megawatts of power in the process.

WATCH: Lights go out across India for Earth Hour

0:58 Lights go out across India for Earth Hour

The WWF says this year’s events include everything from a choir performing by candlelight in Montreal to skating under the stars in Vancouver to a candlelight walk and yoga in Toronto.

Last year’s event saw Prime Minister Justin Trudeau and a number of cabinet ministers join in.

Electrical utilities across Canada have also actively taken part in Earth Hour, though it has prompted some critics to use power usage figures to measure Earth Hour’s success.

READ MORE: How climate change will affect Canadians

Among the famous buildings and structures taking part internationally are Sydney’s Opera House, London’s Big Ben and Houses of Parliament, the Colosseum in Rome, Istanbul’s Blue Mosque, the Eiffel Tower, Moscow’s Kremlin and Red Square, the Pyramids of Egypt and the world’s tallest building, the Burj Khalifa in Dubai.

WATCH: Expect more ‘extreme and unusual’ weather in 2017: report 

2:09 Extreme weather data signals uncharted waters for future of the earth

While the organizers of Earth Hour said they do not audit results of the energy saving initiative, the group has commissioned research indicating up to one in four Australians gets involved.

WWF says Earth Hour can take credit for various environmental initiatives, like the 2013 declaration of a 3.4 million hectare marine park in the waters off Argentina, the planting of a forest in Uganda and a ban on soft plastics in the Galapagos Island.

— With files from the Canadian Press