READ MORE (+PHOTOS): br Hour by hour, the Earth is plunging into darkness on Saturday. The dimming of lights is a symbolic gesture calling on the people to seek a better balance between humanity's desire for consumption and the planet's ability to sustain it.br ­This year's Earth Hour is the sixth consecutive event to take place. What started as a local affair in Sydney back in 2007 now unites 135 countries around the world. This year, the action is dedicated to the Arctic.