Combination photo shows The Eiffel Tower before and after submerging into darkness at 8:30 pm (local time) as part of the Earth Hour switch-off on March 23, 2013 in Paris. Organisers expect hundreds of millions of people across more than 150 countries to turn off their lights for 60 minutes on Saturday night -- at 8:30 pm local time -- in a symbolic show of support for the planet. While more than 150 countries joined in last year&#039;s event, the movement has spread even further afield this year, with Palestine, Tunisia, Suriname and Rwanda among a host of newcomers pledging to take part. AFP PHOTO BERTRAND LANGLOIS