Explain how and why the city expanded in size, population and complexity by 1900?

Okay, i'm going to tell you how it increased in --------- throughout history..... Basically, man settles down nears river to satisfy his need for water............ Indian civilization on the banks of Indus..............Egyptians on the Nile... Over time, man began to use the water to power mills to crush grains and such like. rivers began to be used for transport..... Slowly with the development of the wheel and other inventions that facilitated trade, civilisations began to flourish.... People from distant lands began to hear about these developments and came to see them. Entranced by the then modern city, they began to settle down. This led to a rise in population which in turn increased the demand for goods. This led to an increase in industries. After the industrial revolution. roads and railway lines were set up. these served to bring in a large number of refugees from warfronts and slaves. Steam liners etc. were set up that could cross the oceans faster leading to expansion of trade which in turn led to flourishing of cities.As cities began to grow in population, they began to grow in size and when no more land could be utilised for this purpose, buidings grew taller and taller- skyscrapers which dot the skyline of any major city today.