This Saturday, March 28, marks the ninth annual observance of Earth Hour, a symbolic event intended to raise awareness about climate change. Cities and famous landmarks will turn out the lights for an hour Saturday, along with millions of ordinary citizens. Observed in 162 countries in 2014, the event is about "coming together to create a symbolic and spectacular lights out display and asking for change," according to parent organization World Wildlife Fund (WWF). The London Eye and London skyline can be seen before (left) and after (right) the population of the city observed Earth Hour on Saturday, March 23, 2013.