A walk-in shelter providing protection against undesired heat, radiation, gas and water action, as well as mechanical stressing, particularly for data carriers is proposed, in which the walls comprise several different layers. The inner and outer layers are constructed as a closed metal envelope. Between the outer and inner layers is provided a metal supporting frame and between the outer layer, supporting frame and inner layer are provided insulating layers with high thermal insulation and mechanical strength. All the layers are set up independently of one another, are self-supporting and not mechanically interconnected.