What is a city? Is it a concentration of people with similar cultural, religious, and sociological ideas, or is it simply a concentration of people with a similar economic purpose? Since early civilization the idea of the city has been of great purpose for the inhabitants of an area. From the early Greek-city polis of Sparta and Athens to the power of Rome, cities have undergone many changes throughout the course of time. In the new world economy and society, the idea of the city is taking on new forms. As a former resident of Brussels, I personally have seen a change from the time of my parents to the present day. For example, Brussels has seen a massive influx of immigration from North Africa and Eastern Europe, whereas during my parents' early years immigration was largely stagnant. Another example would be the Dutch cities Rotterdam and Amsterdam...