Cities were first conceived as complex systems in the 1960s. In His Nobel lecture Ilia Prigogine (1977) and later in in his writings Ilia Prigogine uses the city as a metaphor of complexity. However it was Peter Allen who first developed a complexity theory of cities (Allen and Sanglier 1981) and by doing so he started the domain of CTC – complexity theory of cities. Developers need to understand this processes when realizing their real estate projects.