  The main goals of relativistic heavy-ion experiments is to study the
properties of QCD matter under extreme temperatures and densities. The focus of
this talk is the studies that are underway at the Relativistic Heavy Ion
Collider (RHIC), located at the Brookhaven National Laboratory (BNL) on Long
Island, New York, U.S.A. I discuss selected highlights from the past couple of
years that are key to elucidating the characteristics of the new state of
matter created in these heavy-ion collisions, called a Quark Gluon Plasma.
