Towards the Quark Gluon Plasma

We discuss recent experimental results in the field of ultra-relativistic nuclear collisions. The emerging ``picture’’ is a collectively expanding, initially hot and dense fireball in which strangeness- and low-mass di-lepton pair production are enhanced and J/$\mathrm{\Psi }$ production is suppressed compared to expectations from nucleon-nucleon collisions. It is argued that, taken together, these data provide circumstantial evidence that a (at least partly) partonic phase was produced in such collisions.