What the Ground Says horizontal ellipsis

Ground, as a body incised by natural and human actions (European Landscape Convention), carries "stories", going beyond quantitative values. As in a text, it holds the keys to understand what it covers or hides. In its thickness, it shelters "implicit projects". Understanding its complexity requires a physical and perceptual commitment, challenging the body in space: dimensions gradually forgotten by Environmental Sciences. As a "threshold" between visible and invisible, Underground-Built-Heritage represents the reverse of the emerged world: hollow space, both generator and mirror of open space (cities, landscapes). The focus is on physical and mental relationships between these two worlds. Past and present relationships emerge, allowing hypotheses to reconstitute collective memories, practices, knowledge, and values, which serve territorial development. The "Three Countries Park" is a place for cross-border experimentation to test how UBH can rebuild common links for fragmented environments. The cavities of a geo-park (planned) and the tangles of underground mining architecture are the fragments of a vocabulary whose meaning communities have to relearn. Built undergrounds will, thus, emerge from common stories that revive the imagination of populations who have lost all notion of belonging to a place. UBH will become a vector of new territorial coherence linking the physical and mental perceptions of people.