Construction of an underground data center: the extraction of the tuffeau stone, in the Saumurois Region, has led to the creation of thousands of kilometers of underground galeries, which remain unused till this day. The thermal conditions inside the passages offer a unique opportunity to establish highly secured data centers with a high energy performance. In association with Pays de Loire Region, Caisse des Dépôts (Deposits Fund), Saumurois conurbation, Critical Building, Celeste, Elioth, Sigma.