A combination picture shows the Sony Center at the Potsdamer Square before and during (bottom) Earth Hour in Berlin 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/Fabrizio Bensch (GERMANY - Tags: ENERGY ENVIRONMENT SOCIETY CITYSCAPE)
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)