Despite impressive progress in cosmology over the last decade, our understanding of the universe is still limited particularly in some Dark Areas: Dark Matter, Dark Energy & Dark Ages, where progress is particularly difficult. My goal is to assemble a focused research group in a unique environment at the crossroad of astrophysics, cosmology and fundamental physics, to shade new “Light on the DArk” (LIDA) using new analysis techniques and new observations coming from on one side: wide field imaging and spectroscopy galaxy surveys, and on the other side: deep multi-wavelength survey of massive galaxy clusters.