This article raises important issues related to global threats to the urban environment and methods of its protection on a scale from urban planning to architectural design. The research undertaken in this respect was conducted on the selected medium-sized German city of Regensburg/Ratyzbona. This is a city that has for many years been implementing a spatial development policy in line with the principles of sustainable development. The research results obtained present very interesting design solutions for the way they have been implemented in order to constantly improve the ecological effect of urban development. The basic element strongly associated with the sustainable development of Regensburg's buildings is its Urban Greenery System that takes into account the natural and cultural heritage of the city and its suburban areas. This system is, as the research has shown, legally protected and, in a model-based way, expanded both on the scale of the city and of each housing estate. The presented results of research on this type of ecological project also relate to pilot analyses of the construction projects of the “green” Burgweiting-Mitte housing estate and reconstruction together with the restoration of the historic “green” Ganghofersiedlung housing estate.