A combination photo shows a view of National Stadium, also known as the Bird's Nest before (top) and during Earth Hour in Beijing, March 23, 2013. The stadium was designed for use throughout the 2008 Summer Olympics and Paralympics. Earth Hour, when everyone around the world is asked to turn off lights for an hour from 8.30 pm local time, is meant as a show of support for tougher action to confront climate change. [Xinhua]