  Highlights of the results from ultrarelativistic heavy ion collisions at
CERN-SPS are reviewed. In particular, I discuss how the experimental results
indicate that a collective strongly interacting system has been produced, and
what are the implications towards the Quark Gluon Plasma. The physical ideas
behind measuring certain observables are introduced. The future program of high
energy nuclear collisions at BNL-RHIC and CERN-LHC/ALICE is also briefly
discussed.
