“Earth Hour” is the world's largest initiative  in support of the planet Earth and thrift use of its resources.
The outdoor lighting of the main streets and buildings of Yerevan will be turned off on March 27 from 20:30 to 21:30 as part of the “Earth Hour” global environmental event to combat climate change. 
The first Earth Hour event was held on 31 March 2007. Similar event emphasizes the essentail of each citizen to make daily efforts in aa bid to save resources, achieve harmony with nature, and to use energy efficiently.
The  events in Armenia are held on the initiative of the Armenian branch of the World Wildlife Fund.
Those wishing can join the initiative.