Introduction: If in the times of the past, not too far ago, cities were such rare and uncommon phenomena, nowadays they have been turned into the main place of work and life of the major part of human beings of the world. This is to the extent that more than half of the nearly 7 billion people of the world are now living in the cities. This increase of population in cities has brought about numerous problems and challenges including crowd, traffic, problems of air pollution and environment, inequality in access to urban services and facilities, deficiency in infrastructures, corrosion and weariness in the neighborhoods and many other problems and issues...