Greening the city: the ecological and human dimensions of the city can be part of town planning

The industrial revolution brought about a rapid growth in cities as economies shifted from rural to urban industrial production. As more people and industry filled the old "walking cities" of Europe, they became impossible to live in. The wastes in the streets and the pressure for more and more housing in the confined walking dimension of five kilometres or so led to a new kind of city - the "transit city." New transport technology meant that using trams and trains you could link a series of urban villages like pearls along a string. This solution meant that walking scale areas could be retained once a new form of linkage was created, and it meant that natural areas could be retained in the corridors between developments. North American and Australian cities were built this way in the late 19th and early 20th centuries. Many European cities such as Stockholm and Zurich have retained this basic urban form.