Nowadays discussion on global cities concept is being addressed on European level. The concept is a consequence of multiplicities of globalization processes adding different layers according to social, economic and environmental requirements. Cities must also be seen as working systems, with the same needs and requirements in terms of safety and well-being that are considered for other systems. In this paper Authors address the evidences that support the importance of this additional layer. Different sources were used in order to obtain the data related to working systems and their relation to the global cities concept. The conducted systematic review indicate that the search words: sustainability, occupational and global city were not crossed for research. Furthermore, challenges that cities are facing must be understood as additional source of motivation and innovation towards a global city. Cities must also be seen as working systems, with the same needs and requirements in terms of safety and well-being that are considered for other systems