Building skyscrapers, Real Estate has to constantly deal with social, economical and political issues. Nowadays market calls for a less conflictual and more profitable development niche, until now especially limited by livability and psychological constrains coming from the absence of natural light: underground architecture, including earth-sheltered and earth-covered buildings.Hypogeal spaces can tackle congestion, lack of open public space and aging infrastructures, exponentially increasing urban design opportunities to populate the “volume” contained by an over exploited earth surface. Underground can limit visual impact (zeroing main concerns about skyscrapers)and promote efficient land use in a noise and vibration-free environment, reducing energy costs by heat loss and daily temperature fluctuations control.Until now the discomfort caused by sky and sun deprivation consents hypogeal architecture only where protection from harsh climate conditions and natural disasters count more than above mentioned discomfort.SkyCoat, with a great leap underground, recreates the experience of natural light, obtained by complementary presence of both direct sun and diffused sky lights.Disadvantages of hypogeal architecture, like limited or no natural light and negative psychological reactions, are blown away by the possibility of reproducing the sun and the sky many meters under the earth surface, therefore opening a new and unexplored territory for real estate investors, architecture designers and buildings end-users.SkyCoat technology will also be verified in light design, testing how housing, offices, retail, industry and transport, can benefit from indoor natural light reproduction. At the same time, SkyCoat will be tested as coating material for skyscrapers: a thin layer of a nano-structured dichroic material will reflect warm sun light and scatter complementary cold sky component, allowing a tailor-made silhouette not necessarily corresponding to the building volume