During the history, some cities were considered as gates of commerce, culture and information. They were the reasons and the focal points where the people from different regions used to leave their homes, in the aim of a better education, work, food and adequate quality of life. While the time was passing, the world’s population expanded quickly, the lands started to be fully occupied and the competition to find jobs increased. Also, the type of work, skills, sectors and services changed from an agricultural and mostly physical jobs to skilled, specified, complex services based on financial flows, technological systems and international companies instead of local workshops, accompanied by a fast production system accomplished by smart machines without relying on the complete human physical and even mental help.