epaselect epa04684248 A composite picture of the Eiffel Tower with its lights switched on (L) and off (R) for the Earth Hour 2015 in Paris, France, 28 March 2015. 170 countries and 1200 monuments’ lights are to be switched off at exactly 8.30pm local hours, taking part in the operation Earth Hour for its 2015 edition. Launched by the World Wide Foundation, the event is meant to highlight the importance to fight global warming. EPA/ETIENNE LAURENT