Seven thousand cities in 162 countries across the globe are turning off their lights for Earth Hour this year. Each city will dim their skyline beginning at 8:30 p.m. local time on Saturday.

Earth Hour started in 2007 as a World Wildlife Fund event in Australia and has grown to become a global message that citizens across the world must work together to fight climate change. Some of the world’s best-known landmarks will go dark this year, including the the Eiffel Tower in Paris, the United Nations building in New York City and the Cristo Redentor in Rio de Janeiro.

This year’s earth hour takes on extra significance ahead of the UN meeting on climate change in Paris scheduled for December.

Read next: Antarctica May Have Just Set a Record for Its Hottest Day Ever

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Write to Eliana Dockterman at eliana.dockterman@time.com.