Building a home is a basic human need that engages each individual. But never before have so many people lived on earth. By 2050 there will be more than 9 billion people on earth. Most of them in bigger and bigger cities. But man faces a future in which the environment will be polluted. Do alternatives exist? Visionaries and inventors deal with this question. Their craziest projects are to turn Paris into a tropical forest, to furnish apartments with intelligent furniture, to build self-sufficient houses, or to create objects by means of a 3D printer. Not least - a life at the bottom of the sea, or on the moon!