The construction of this small chapel starts from the need of the adjacent church to introduce light. Thus, the project arises from a single reflection, creating "a box for the Light", with the double meaning of being a box that contains light for the rest of the temple and of being a place that will contain the Light for all Christians: The Blessed Sacrament. The search for light, possibly the most important task of any architect, has become latent in this project by making a container space that, because of its orientation and zenith opening, is capable of introducing clarity throughout the church. Thus, the entire surface will be white and clean. Following this same sense, the floor of the rest of the temple will be changed with the objective of a greater luminosity. The search for an essential space, naked, without any element that can distort the radically important in a sacramental chapel, has led us to opt for a Franciscan architecture, sober, clean of forms and adornment. The precision sought in a space of these characteristics will be determined by a strict geometry, radical, without any option that can be reason for dispersion.