During this year's campaign, conducted by the World Wide Fund for Nature nongovernmental organisation, landmarks in 7,000 residential areas in over 150 countries were plunged into darkness for an hour to give their contribution to efforts to raise the awareness of responsibility towards the environment.

The first "Earth Hour" event was held in March 2007 by the WWF and the Sydney Morning Herald when 2.2 million homes and businesses in Sydney turned off their lights for an hour.

Earth Hour coordinator in Croatia Petra Boic-Petrac said Croatia joined the campaign four years ago and that last year street lights went out in 38 towns.

On Saturday evening, Environment Protection Minister Mihael Zmajlovic arrived at the square in front of the Zagreb Cathedral which were also without the electric public lighting for an hour as part of the campaign, to support Croatian activists who organise "Earth Hour" actions.