Reported on Yahoo news:

Australia’s largest city will be plunged into darkness
for an hour on Saturday in an attempt at a world first blackout to
raise awareness of global warming, organisers say.

A successful switch-off could then be copied by major cities around the
world in a drive to reduce the greenhouse gas emissions blamed for
climate change, according to international conservation group WWF.

A thousand businesses have signed up, including many of the top
blue-chip companies on the Australian stock market — and even
McDonald’s is going to turn off its "Golden Arches" signs.

Photo: vm1757/Flickr