By 2050, another 2.5 billion people are going to require housing. The question is: How will the future of mankind be constructed? Concrete and steel consume vast amounts of energy and produce greenhouse gases on a scale we can no longer afford. This documentary series shows we already have answers: Researchers around the world are developing building materials that are not only significantly more environmentally friendly, but could even be used to "fix" climate change. Hybrid constructions of plants and architecture could provide vital cooling in increasingly hot metropolises of the future. It is not unusual for the materials of the future to come from the past – and are combined with new, exciting technology.