Abstract
In order to make human life everlasting, it is essential to recover nature in the midst of the urban areas in the most developed countries. The possibility of a mega-structure which plays a role of a basis of the renovation of urban areas compatible with the recovery of nature is discussed on condition that human life must be kept pleasant and free from any restraints. The megastructure obtained is of a scale of 10 stories with 100 m of story height and 1 km^2 of total areas. One structure can support urban life of twenty thousands people, emancipating 0.9 km^2 of ground surface from the monopolized use of human being.