  At high energy, the gluon distribution in nuclei reaches large densities and
eventually saturates due to recombinations, that play an important role in
heavy ion collisions at RHIC and the LHC. The Color Glass Condensate provides a
framework for resumming these effects in the calculation of observables. In
this talk, I present its application to the description of the early stages of
heavy ion collisions.

High Energy Physics - Phenomenology;Nuclear Theory