Individuals, businesses, and organizations around the world participated in Earth Hour on March 31. This global observance is held to demonstrate how much we can do to cut back power use and stop climate change if we all work together. Participants shut off their lights from 8:30 to 9:30 p.m. local time, causing a wave of darkness to sweep across the Earth’s 25 time zones.

The next Earth Hour will be on March 30, 2013.

Learn more about Earth Hour.

Get more power saving tips from National Geographic Kids.

Photograph by Jorge Sierra, WWF Spain

Turn off your lights this Saturday, March 28 from 8:30 to 9:30 local time and participate in a global observance called Earth Hour. Individuals, businesses, and organizations across the world will be participating (National Geographic included). Earth Hour is a demonstration of how much we can do to cut back power use and prevent climate change if we all work together.

The first lights-out will be in the Chatham Island off the coast of New Zealand. From there, the wave of darkened buildings, streets, and monuments will ripple through all 25 time zones. Even the Eiffel Tower will go dark.

The more participants there are, the bigger the impact will be. So get ready to power down!

Learn more about Earth Hour.

Read about last year’s Earth Hour on National Geographic News.

Get more power saving tips on National Geographic Kids.