The Residual Spaces of Developmental Urbanism as Opportunity for Green Cities and Improvement of Human Wellbeing

City densification and greening are two priority urban-policy objectives, for the coming years, aimed at making cities more resilient to climate change, slowing the spread of urbanization and improving the quality of life in cities. These are sometimes contradictory objectives that require fine and deep analysis to create approaches and methods that combine them. The most recent research has presented so-called small urban green spaces (SUGSs) as a viable alternative to achieve this double objective. This was the starting point of this research, which used GIS digital analysis and microscale fieldwork to study the possibilities of greening an excessively dense and low-quality urban space in the city of Pamplona (Spain). The results thereof showed that the urban structure of this neighbourhood contains a large number of small spaces with no specific use or function—residual, surface and vertical spaces—and that are simply undefined remnants between buildings and streets, or party walls that were never built. Only these surface spaces occupy a total area that is twice the size of the existing green spaces. Based on these results, this work explores the possibility of increasing the green areas of the neighbourhood through new SUGSs and the creation of a green corridor that increases environmental and social connectivity and the quality of life in the studied space.