Hundreds of world landmarks from Berlin's Brandenburg Gate to the Great Wall of China went dark Saturday, part of a global effort to highlight climate change.
Earth Hour, held on the last Saturday of March every year, began as a Sydney-only event in 2007. The city's iconic Harbor Bridge and Opera House were dimmed again this year.
Image: People use candles to create the number 60, representing the minutes in an hour, to mark Earth Hour in La Paz, Bolivia on Saturday, March 31st, 2012. Earth Hour takes place worldwide at 8:30 p.m. local time and is a global call to turn off lights for 60 minutes, as a symbolic act to raise awareness about climate change and to make people aware of everyday energy use.