Presently we are living in the urban century. In approximately 30 years 2.4 billion more people are expected to live in cities, so the 21st century can be rightly called the urban century. Humanity is witnessing and participating in the greatest migration from rural into urban places, since migrants move into new urban areas. In only 10 years it is expected a new area of 1.2 million square kilometers to be built to accommodate the needs of millions of people. The cities of the future are being developed on an epic scale. This begs the question: why so many new cities are being developed? Two factors have been identified by demographers: push and pull factors. The push factors are negative and include the lack of financial prosperity in rural areas, as well as political instability. However, there are pull factors, which include the benefits from living in urban areas. The principal reasons for the growing popularity of cities is the larger number of people, their proximity, and the financial opportunities. People are social beings who wish to interact with each other, so living in cities might even be considered their natural habitat.
