The UNESCO World Heritage Cologne Cathedral and the Hohenzollern railway bridge along the river Rhine, are seen during and before (top) Earth Hour, in this combination picture March 29, 2014. Lights go off around the world at 8.30pm local time in a show of support for renewable energy during Earth Hour, an event organised since 2007 to promote a sustainable future for the planet. REUTERS/Ina Fassbender (GERMANY - Tags: ENVIRONMENT TRAVEL SOCIETY ENERGY)
A combination picture shows a view of the hill of the Acropolis before (top) and during Earth Hour in Athens March 29, 2014. Lights go off around the world at 8.30pm local time in a show of support for renewable energy during Earth Hour, an event organised since 2007 to promote a sustainable future for the planet. REUTERS/Alkis Konstantinidis (GREECE - Tags: ENVIRONMENT SOCIETY TRAVEL)
The Gateway of India monument is pictured during Earth Hour in Mumbai March 29, 2014. Earth Hour, when everyone around the world is asked to turn off lights for an hour from 8.30 p.m. local time, is meant as a show of support for tougher action to confront climate change. REUTERS/Mansi Thapliyal (INDIA - Tags: ENERGY SOCIETY TRAVEL)