United Nations Secretary-General Ban Ki-Moon has called on the world to observe Earth Hour in solidarity with 20% of all humankind, who live with no access to electricity. Ban said Earth Hour, has the potential to be "the largest demonstration of public concern about climate change ever attempted." This year 147 countries and territories, a record number, have pledged to turn off lights to show a unified global commitment to save our planet. Up to a billion people worldwide are expected to participate in this global voluntary blackout by switching off their lights from 8:30 p.m. to 9:30 p.m. on March 31^st local time.