The city is a crystallisation of human civilisation. Just as the American social philosopher Lewis Mumford put it,"the city is a special structure which, fine and compact, has been designed to preserve the fruits of human civilisation." Many Western languages have derived their versions of the term "civilisation" from the same Latin word "civitas"(meaning "city" ), and it is by no means a coincidence. By virtue of its embracing and regenerating nature, the city has played a significant role in the perfection of order in human society.