The Relativistic Heavy Ion Collider (RHIC) at

of Energys flagship research facility for the nuclear physics program. The construction of the collider and a complementary set of detectors were completed as scheduled during 1999. Following the initial verification of functionalities of the collider in the same year, collisions of Au ions were achieved during the subsequent commissioning run in the year 2000, first at the collision energy of 56 GeV per nucleon on June 12 and later at 132 GeV per nucleon. All four detectors, BRAHMS, PHENIX, PHOBOS, and STAR, were also commissioned and collected significant amounts of data during the four-week run period. This report gives an overview of the RHIC facility, its commissioning activities, and the first physics results at the new frontier of nuclear matter research that is opened by RHIC.