Lights will go off in some 7,000 cities around the world for this weekend's Earth Hour event, which will aim to raise hundreds of thousands of dollars for environmental projects worldwide, organisers said Thursday. Organisers WWF have partnered with payments giant PayPal to allow donors to contribute for specific projects in countries from Russia and India to Canada and Indonesia, using Asian fundraising site Crowdonomic. "We are starting with around 20 projects this year, but our vision is to really expand once Saturday's event has taken place," said Earth Hour chief executive Andy Ridley. "The projects have been chosen based on their scalability, so even if the target has not been met, a small amount of funds raised will still help implement an outcome on the ground." Projects under the "Earth Hour Blue" crowdfunding scheme -- which aim to raise more than $650,000 in total -- include a turtle centre in Italy and funding for forest rangers in Indonesia. Earth Hour will see world landmarks including the Empire State Building, the Eiffel Tower and the Kremlin switch off their lights for 60 minutes at 8:30 pm local time on Saturday. The event is being marked in more than 150 countries, organisers said. The event is being coordinated from Singapore, with the stars of new movie "Amazing Spider-Man 2" set to help switch off lights on the city-state's skyline in the upmarket Marina Bay district. Sofiah Jamil, adjunct research associate at Singapore's S. Rajaratnam School of International Studies, who has been campaigning forenvironmental causes in Southeast Asia, welcomed the funding initiative. "At the very basic level, such crowdfunding activities can potentially increase the visibility of Earth Hour and in turn awareness on environmental action," Sofiah told AFP. "I think the main way in which this is effective is that it allows a way of involving a wider section of people, who would previously perhaps not be involved, such as those with limited knowledge on how they can contribute and those who want to contribute with ease and convenience," she said.