The need of country-states and their public administrations or institutions to find ways and solutions that can ensure general sustainability, and more recently, social-ecological resilience, has been increasing over the last decades. Both public and private activities have been developing in a more ecological way, or at least trying not to compromise the environment and ecosystems as much as possible. The global trend has been, therefore, to implement the best measures for the efficient use of the natural resources that are available on the surface of the Earth. It is a challenge for human communities and their institutions to organise access to common resources and find solutions to live within the limits or boundaries of our planet. Simultaneously, the protection of the rights (both individual and collective) and the well-being of the communities that live in different territories is a priority of our time. Because ecology is, in fact, a synthesising science of both humankind and nature. This synthesis leads our attention to the reality of cities, whose importance has been increasing, namely in the last decades. As growing places, cities pose many of the most significant governance problems to the world in the twenty-first century.