Cities around the world celebrated Earth Hour Day by going dark for one hour during the evening.
Landmarks and buildings honor the campaign by shutting off all of the lights at 8:30 p.m. local time.
The Eiffel Tower in Paris stopped its light show for an hour, and the Acropolis in Athens plunged into darkness. Buildings in Hong Kong, Moscow and Mumbai also went dark for the global event.
Earth Hour is a call-to-action campaign raising awareness about climate change and the effects it has on the environment. The event also calls for the reduction of certain energy sources, such as fossil fuels, that could produce more carbon in the atmosphere.
The movement started in 2007 and has been continued on by the World Wildlife Fund. It has spread to more than 180 countries around the world in that time.