National landmarks switch off lights for Earth Hour (4)

（People's Daily Online）  14:03, March 25, 2013  

7th Earth Hour was marked from 8:30 p.m. to 9:30 p.m. around China on March 23, 2013. Earth Hour is a worldwide event organized by the World Wide Fund for Nature (WWF) and held towards the end of March annually, to encourage household and business turning off non-essential lights for an hour to raise awareness about taking responsibility of earth protection and taking action against climate changes and global warming.