The Texas Medical Center (TMC) is a 2.1-square-mile (5.4 km2) medical district and neighborhood in south-central Houston, Texas, immediately south of the Museum District and west of Texas State Highway 288. Over sixty medical institutions, largely concentrated in a triangular area between Brays Bayou, Rice University, and Hermann Park, are members of the Texas Medical Center Corporation—a non-profit umbrella organization—which constitutes the largest medical complex in the world. The TMC has an extremely high density of clinical facilities for patient care, basic science, and translational research. The Texas Medical Center employs over 106,000 people, hosts 10 million patient encounters annually, and has a gross domestic product of US$25 billion. Over the decades, the TMC has expanded south of Brays Bayou towards NRG Park, and the organization has developed ambitious plans for a new "innovation campus" south of the river. The 4.93-square-mile (12.8 km2) Medical Center / Astrodome area, highly populated with medical workers, is home to over 20,000 people. The TMC is serviced by the METRORail Red Line, a north-south light rail route which connects the district to Downtown Houston and NRG Park.