Final answer:
Urban Design is the key aspect of architectural and city planning that is concerned with the design of urban spaces and structures, which includes planning for public transportation, safety, functionality, and aesthetics in the context of a city's overall layout and lifestyle.
Step-by-step explanation:
The aspect of architectural and city planning that deals with the design of urban structures and spaces is known as Urban Design. Urban Design encompasses the creation and organization of urban spaces to ensure they are functional, appealing, and in harmony with the overall fabric of the urban environment. It involves considerations of the layout of cities, the design of public spaces, the integration of infrastructure, and the interaction between different components of the urban ecosystem.
With the onset of the new millennium, architecture has evolved to incorporate new concepts and mixed-use facilities that align with compact urban living and public transportation. The architects of these radical designs serve as efficient and functional artists who address today's energy requirements while considering lifestyle changes, transportation needs, and the necessity for public lands.
Furthermore, architectural designs account for both safety and stability, coping with the various physical loads and environmental challenges they may encounter. Architects perform crucial roles in formulating the overall urban morphology, which influences not only city planning but also the cultural, political, and social characteristics of the urban area.