This major exhibition outlined how the Berlin IBA set about its main project: rebuilding the city. It displayed historical documents, pictures of the city before and after the air raids during the 2nd World War, building projects, town plans, ideas, models and utopian plans. A large model of the rebuilt city welcomed visitors at the entrance to the exhibition: a "sunshine machine" was designed to light it up: steel cables stretching from wall to wall for accommodating a sliding "cart" fitted with a revolving arm holding a light source. This imitated the daytime ecliptic across the city. The installation featured sloping panels displaying drawings and photographs, and the premises were lit by stretched cables from the "Scintilla" system with sets of low-voltage lamps projecting direct, one-directional light of optimum rating and colour temperature. The information boards are lit up automatically by photocells as visitors approach them.