Sustainability is the starting point of this study, it has become a crucial subject especially since in 2015 the Sustainable Development Goals were defined. Over the years different definitions and branches of sustainability have been delineated in order to adapt to specific projects and studies, here a few of them classical and related to urban life and social aspects have been presented. Tools have been defined and are being used every day to move forward in the scientific research, to influence the definition of actions and policies. Sustainability is the thread that brings the whole study together, motivating the definition of solutions and guidelines that should be pursued.