Combination photos. 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. 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. [WWF/EARTH HOUR GLOBAL]