On Saturday night, people around the world turned off their lights to mark Earth Hour: a campaign to save energy and call for tougher climate change action.
Landmarks around the world went dark for an hour, including Saint Basil's Cathedral in Moscow.
London's Houses of Parliament and Big Ben.
The Hungarian parliament in Budapest.
Vienna City Hall in Austria.
Berlin's Brandenburger Tor gate.
The Serbian parliament building in Belgrade.
Belgrade's Saint Sava Church.
The Acropolis in Athens.
The Spanish Royal Palace in Madrid.
The Leifeng Pagoda in Hangzhou, China.
David Mack is a reporter and weekend editor for BuzzFeed News in New York.
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