Large residential developments like the Japanese “Danchi” went through an enormous international boom, particularly in the decades that followed the Second World War; they provided modern, affordable living space for rapidly growing populations. The banlieues in Paris are remnants of that period as are the Märkisches Viertel area in Berlin, prefabricated large-scale socialist developments, and the Danchi; largely built in the nineteen-fifties to seventies. Yet, this type of public apartment building has long fallen into disrepute. Many are threatened by vacancy, decay and demolition—wrongly so says MIKAN, a Japanese-French team of architects. They have come up with a sheer inexhaustible range of ideas of how to convert, re-function and re-use such mass developments. Their aim: to protect them from decay and vacancy and to discover their hidden qualities. Save the Danchi shows how surprisingly easily and accessibly this uncomplicated architecture can be adapted to contemporary needs and ecological standards.