After extensive archaeological excavations, the new car park built north of the city of Sion (VS) came out of the ground. The structure is located near buildings occupied during the work. Berlin walls, nailed to the excavation support and excavation retaining nails take over the neighbouring buildings as an underpinning. Deployed on three underground levels, the reinforced concrete structure is composed of slab floors supported by prefabricated pillars with high load capacity. The car park will have a capacity of 270 spaces, 7 of which will be equipped with charging stations for electric vehicles.