This major exhibition illustrated how the Berlin IBA set out to reach its main goal - the rebuilding of the city. It displayed historical documents, images of the city before and after the devastation of World War II, building and town plans, proposals, models and utopian visions. A large model of the rebuilt city welcomed visitors at the entrance to the exhibition, and the “sun machine” was designed to light it. Steel cables were stretched from wall to wall to allow a "cart" - fitted with a revolving arm that held a light source - to slide along them, thus imitating the sun’s daily ecliptic movement across the city. The exhibition setup featured sloping panels displaying drawings and photographs, with information boards containing photocells that lit up automatically as visitors approached them. The premises were illuminated by the stretched cables of the “Scintilla” system with mounted sets of very low-voltage bulbs that projected direct and omnidirectional light of outstanding color rendition and temperature.