DEEPLITE-LIGHT FROM THE SKY IN UNDERGROUND SPACE The DeepLITE project was born with the intent of bringing full visibility, appreciation and a well-carved market debut to a revolutionary concept for the indoor reproduction of natural illumination, which had previously gained the support of EC by means of two-years funding in the context of a FP7 Capacities project which had lead to the conclusion of the R&D phase. The goal of DeepLITE is to give strength - through carefully planned events directed to lighting operators and the general public - to a technology which is in the delicate phase between having ready the first product prototypes with high commercial potential and the development of a solid business. The possibility to introduce natural, outdoor lighting in the indoor may be seen as a sort of philosopher's stone in the field of contemporary lighting design. The effect of sunlight -which is warm, directional, and defines volumetrically the geometry of objects- combined to the effect of skylight -diffused, cold, soothing, capable of endowing shades with a soft blue tinge- has a unique role in the relationship that human beings develop with architectural spaces. As a philosopher's stone would do, the use of natural light in an indoor environment where only standard artificial light sources are allowed modifies its own essence: that is, the way it is seen by visitors, both in terms of emotional memory as well as of perception of dimensions. Up to now, no solutions available on the market are capable of reproducing the full features of natural daylight by means of artificial sources. The current answer to this issue is an architectural design that develops around the concept of providing apertures and structures that let daylight shine in with a number of effects. Of course, in absence of commercial luminaires capable of reproducing natural light, the problem is unavoidable as far as architectural spaces with no visual access to the outdoor -such as hypogeal- are concerned. The CoeLux project (2010-2012), funded by EC in the FP7 Capacities programme, has vitally contributed in constructing a viable solution to this problem. The lighting technology developed in the course of the project is based on a fundamental consideration: no daylight is truly simulated without the combined reproduction of sunlight and skylight. As strikingly simple as it seems, this fundamental concept is neglected by luminaire producers aiming at mimicking natural lighting, who focus their efforts on either sun spectra reconstruction, or providing observers with the view of a fake sky in the form of panels that diffuse blue light. The effects obtained by separating the two elements are way far from the physical truth of daylight. The main milestone of the DeepLite project consisted in assessing the applicability of this revolutionary technology, thus bridging the gap between research and development and the market. This was successfully achieved with the realization of eight installations, presenting the CoeLux® technology in different architectural environments and applications sectors - healthcare, retail, office, museum and transportation. The worldwide uproar generated by these installations, supported by numerous events and dissemination activities, have demonstrated that CoeLux® has the full capability of promoting a change in the global lighting market leading to an impressive economic impact.