Agence France-Presse: Millions of people across the globe will kill their lights for one hour this Saturday, in what organisers hope will be a resounding call for tough action on climate change. The waters of Sydney Harbour will be plunged into darkness for an hour from 8:30 pm (0930 GMT) as the iconic Opera House and Harbour Bridge dim their lights. The pyramids of Giza, Niagara Falls, the Eiffel Tower, the Empire State Building, the Acropolis and Beijing’s “Birds Nest” Olympic stadium are among …