Philippe Rahm Architectes Philippe Rahm Architecture and urbanism were traditionally based on climate and health, as we can read in the treatises of Vitruvius, Palladio or Alberti, where exposure to wind and sun, variations in temperature and humidity influenced the forms of cities and buildings. These fundamental causes of urban planning and buildings were ignored in the second half of the 20th century thanks to the enormous use of fossil energy by heating and air conditioning systems, pumps and refrigerators, that today cause the greenhouse effect and global warming. The fight against climate change forces architects and urban designers to take seriously the climatic issue in order to base their design on its the local climatic context and energy resources. Faced with the climatic challenge of the 21st century, we propose to reset our discipline on its intrinsic atmospheric qualities, where air, light, heat or humidity are recognized are real materials of building,