Earth Hour began in 2007 when most of Sydney, Australia shut off its lights for an hour to raise awareness about climate change. In the past four years, the event has spread world wide, as seen in the video above. Now, major landmarks all over the world will go dark tonight as a reminder that the Earth is a resource shared by over six billion human beings. Even YouTube got in on the act today by adding a lightbulb to their logo and clickable light switch that toggled the website between a light and dark mode.
For those interested, the Earth Hour website encourages you to shut off all your lights for an hour tonight at 8:30 pm local time.