The PHENIX (Pioneering High Energy Nuclear Interaction eXperiment)

at the Relativistic Heavy Ion Collider/Brookhaven National Laboratory

is designed to perform the broadest possible study of nuclear as well as

elementary proton-proton collisions in order to investigate nuclear

matter under extreme conditions. The first experimental signature for

the formation of the deconfined quark-gluon plasma (QGP) was recently

revealed in high transverse momentum hadron production.

In the first part of my talk, the details of this so-called jet quenching

phenomenon will be discussed. In the second part, the future projects

in relativistic heavy-ion collisions at the German Heavy-Ion Research

Center (GSI) and the European Organization for Nuclear Research (CERN)

will be presented.