On last Saturday, March 25, 2017 the Earth Hour campaign took place around the globe arranged by the World Wildlife Fund (WWF). Thousands of organizations and millions of people in 187 countries turned the light off at 20:30 as a symbolic act to attract the attention to ecological problems of the planet.
Details are provided on the official WWF website: http://wwf.panda.org/uk/?296090/eh2017-record
