http://en.wikipedia.org/wiki/Urbanization: Urbanization occurs naturally from individual and corporate efforts to reduce time and expense in commuting and transportation while improving opportunities for jobs, education, housing, and transportation. Living in cities permits individuals and families to take advantage of the opportunities of proximity , diversity, and marketplace competition.

Attention is almost exclusively given to the city, cf. Habitat 2006. or just now: "The theme of the Exposition 2010 Shanghai is "Better City, Better Life". The topic has its origin in the thousands of years of human civilization. In the meantime, the selection of the theme is the continuity of the 154-year tradition of the World Expo, whose theme always reflects a common concern or interest of man kind at a particular historical stage."
"There is no denying , however, that the city today, due to its high-density living pattern, is faced with a series of challenges, such as spatial conflicts, cultural collisions, resources shortage and environmental degeneration. With the fast urbanization of human society going on, how to improve the functioning of cities as the major carrier and mechanism of modern human life, and how to build a harmonious relationship between cities and their rural hinterland - these are increasingly becoming global agendas." [2]

Urban areas cover less than 2% of the land mass of our planet. Roughly the same area as the rainforests.

List of Cities by Population: [3] Entire agglomerations [4]

Whilst for hundreds or even thousands of years the urban - rural distribution of human population has been relatively stable, there seems to be a self - reenforcing trend of rural flight that repeats itself like a pattern in various forms.

There is an invisible threat to the functions of cultural landscape. The cooperation of man and nature which results from permanent cohabitatiion is essential for many functions that are essential for the cities themselves.

Christopher Alexander writes bluntly in his second pattern "Distribution of Towns". "If the population of a region is weighted too far toward small villages, modern civilisation can never emerge; but if the population is weighted too far toward big cities, the earth will go to ruin because the population isn't where it needs to be, to take care of it." [5]

What are the functions of rural areas? We often refer to them as "lungs", since the rural ares clean and regenerate air and humidify it, but there is much more to it:

• Source of high quality nourishment
• Recreational space for those who need a break from urban overload
• Source of health and wellbeing by resonating with natural environments
• Source of materials and energy - in many cases managed as renewable and self- replacing resources. sometimes exploited, sometimes fallback in crisis.
• Respository and retention space for water
• Repository of Biodiversity - Russian biologist Vavilov has found out that certain cultures were niches for great genetic diversity of useful plants and animals, and the rural ares serve as storage centers for those natural assets. (ThisWiki:UweChristianPlachetka/VavilovCultures/IntroDuction)
• Repository of cultural originality and identity Landcape holds human memory and diversity in forms of cultural patterns, artefacts, skills and knowledge.
• Space of mobility and linkages, roads, rails and pipelines. The essential function of in - between to which rural areas globally are being largely reduced.