Introduction: Definition of City and Public Spaces

Nowadays most of the world population lives in the cities. This has been the case since the end of the twentieth century. Megacities are usual in countries with poor services and infrastructure which do not reach their rural areas. In this context, green areas fulfil a vital role, protecting the city’s air, soil and water and allowing inhabitants to lead a healthy life. However, only in a few cases is this goal achiveved, so it is becoming more necessary not only from the point of view of how urban ecosystems function but also considering inhabitants’ need of leisure and health. To attain this, there is a search for city models in which emissions are calculated and reduced and ecosystems are restored and re-naturalized. The proposal implies re-thinking the hectic, fast-pace city life. Development of sustainable and livable cities is under debate. This chapter defines and discusses the concept of public spaces and green areas. The problems of Lima city are presented as well as the difficulty and need for Lima to have enough spaces to meet this need. Given the new challenges posed by the growth of cities and the changes in the relationship between the urban and the rural, we must consider the UN’s Sustainable Development Goal 11, focusing on sustainable cities: how to “make cities and human settlements inclusive, safe, resilient and sustainable.”