Special Edition Rio+20 - the United Nations Conference on Sustainable Development, June 2012.
This special edition was published on the 2009 United Nations Climate Change Conference in Kopenhagen and is all about green technologies. In the spotlight: Renewable Energies, Energy Efficiency and Tomorrow's Power Grids.
The special edition "Green Cities" deals with sustainable solutions for buildings, traffic and energy that could contribute to make big cities more environmental friendly.