Since the 1950s, the alluvial soil of Regensdorf has supplied the Zurich agglomeration with raw building materials, and a few decades later, the holes could be filled with waste. Agricultural land sacrificed, but in the service of a growing city. The surfaces of these anthropogenic soils were either covered by buildings, or hidden under half a meter of top­soil to be cultivated, or simply left to be abandoned before a precise function was assigned to them. Before man drained the plain for agriculture, large marshes covered the lower valley. The water table is very high and the soil is full of water. It is said that nature is resilient and can absorb the contamination of human activity. One of the main functions of soil is to filter water. But what happens when the soil is no longer soil and human activity continues to grow? Through a slow transformation, the project proposes to restore the soil of this site to its filtering and productive capacity while offering users a transitional and open landscape between the village of Regensdorf and Dällikon. No building materials will be imported to the site, all raw materials will be provided locally: gravel, sand, clay, and rubble will be mixed and reorganized to shape a new geology and plants, selected for their primary function, will be the main actors of the project.