A combination picture shows Hofburg Palace before and during Earth Hour in Vienna

A combination picture shows Hofburg Palace before (top) and during Earth Hour in Vienna March 23, 2013. Earth Hour, when everyone around the world is asked to turn off the lights for an hour from 8.30 pm local time, is meant as a show of support for tougher actions to combat climate change. REUTERS/Heinz-Peter Bader (AUSTRIA – Tags: CITYSCAPE ENVIRONMENT SOCIETY TRAVEL)