What do you notice when you move around in densely populated urban areas? That we expand both in width and in height in our building mania and growing trend of urbanization. But shouldn't we pause here and think about how and with what we are building our urban environment? Do we want eternally growing urban areas and their "fat belts" with peripheral residential, shopping, commercial and industrial areas? Or do we want compact urban environments with good accessibility and aesthetic and architectural first-rate spatial qualities? What influence does increasing urbanisation have on our cities and, above all, on future land requirements and use? How do we enable centrality of our daily activities and needs as well as sustainability in our urban living space? What role does underground space play in the creation of new living spaces in cities and urban areas of the future?