Since the first urban developments we seek for the ideal form of our cities. From the ancient plans and philosophical discussions through the medieval New Jerusalem and the ideal cities of Renaissance to the ideals of the modern age: garden cities, linear city, functionalist approaches. Some of those ideal cities were built, development of Canberra is a nice example. Current seeking for the ideal form of our settlements started with the Athens Charter, today it is concentrated on the sustainability of the urban developments and many documents define our goals and tools to achieve them: Agenda 21, Habitat, Melbourne Declaration, Aarlborg Charter or Shinzen Declaration are the most important ones.