  RHIC data opens new ways of characterizing the medium created in a heavy ion
collision by measuring particles with high transverse momentum. In addition to
the observation of the predicted jet quenching, the new data on particle
correlations indicate that a strong modification of the jet-like shapes is
driven by the dynamical properties of the medium. I will review the lessons we
are learning from RHIC and outline some new directions which could become of
primary importance at the LHC.
