The increasingly prevalent development of planning underground urban spaces and their application in urban environments raises new questions related to the design of underground structures. Specifically, the challenges in designing underground structures within the geological space and the emergence of new imaginary representations in the world of architecture necessitate a reevaluation of the role of the underground architect in the future and the further advancement of urban environments. This paper explores new approaches to urban design that would help address the current ecological and sociological challenges faced by today's urban environments. As a model, existing underground spaces in Helsinki (Finland) were studied, focusing on how, through architectural and sensory perception, these spaces can evolve into eco-socially acceptable areas, overcoming the current limitations posed by established practices, regulations, and standards. The methodological approach is based on a dialogue between multiple scientific fields: architecture, urbanism, cognitive sciences, geology, and engineering. The aim of the research is to develop specific methodological tools for future underground architects, which would enable a better understanding of underground urban spaces, their sensitivity in pushing the boundaries of design, and their integration into existing urban environments. In addition to revealing that the role of the architect in a highly technical technological environment is complex, the paper also demonstrates a structural gradation from the geological dimension to architectural space, through human perception, to the graphic and sensory representation of underground structures, thereby illustrating the specific methods used in the study of selected underground spaces. As a result, guidelines and recommendations emerge, intended for project managers seeking tools to mobilize new skills in the field of underground space/structure design. Therefore, this paper should not be interpreted as a list of reproducible solutions for every territory but rather as a sharing of research tools and methodologies applicable in professional practice.