Man has always lived in groups. It was not however until human groups began living a more or less sedentary life that settlements or communities appeared. The eminent economic historian N.S.B Gras propounded the theory that a nomadic economy and the latter preceded the village community by a collectional economy that was the most primitive. Villages developed into towns when a class of traders settled permanently in the villages and began trading from their homes. Finally when conditions were favorable the towns developed into metropolises or large cities that according to Gras appeared with the rise of empires and nation states. Gras contended that the following conditions must be present in order for a metropolis to arise- considerable natural resources, good transportation conditions-land that lends itself to the construction of highways with a location near navigation water but a considerable distance from other large cities and a temperate climate. Charles Cooley put forth the theory that the development of large cities is primarily due to a break in transportation that is an interruption in the movement of goods for the purpose of transferring them from one type of conveyance to another. He distinguished two types of Breaks the physical and commercial both of which may be involved at the same time.
By the first he meant mere physical transfer or storage of goods and by the second a change in ownership. Transfer necessitates various activities that bring people together. People cooperate to unload and store the commodities and to complete the financial transactions involved in the transfer of ownership. This procedure requires warehouses and financial institutions each with its personnel. The person engaged in various tasks the primary workers attract other secondary workers who cater to their needs.
Consequently houses have to be built and hotels, shops have to be established. Institutions and organizations of all types must befounded to satisfy the need of the people. The more extensive the activities connected with the break in transportation the greater is the number of people involved. The concentration of people and activities stimulates production. Commercialdevelopment induces industrial activity. Metropolitanism manifests itself in a remarkable development of subordinate communities around a central city or their orientation towards it so as to give the arrangement more or less of an integrated unity.R.D McKenzie in the Metropolitan Community showed that the development of each of the three types of transportation- water, rail and motor had a specific influence upon the course of city development in United States. These three types of transportation played effective roles in certain periods corresponding to phases of urbandevelopment. The water transportation period was important upto 1850 and marked the development of urban communities along the seacoasts, lakes and navigable rivers. Rail transportation made possible the growth of cities and towns at Junction Island.