Founded in 1811, Massachusetts General Hospital is the earliest and largest teaching affiliated hospital of Harvard Medical School, and one of the three oldest hospitals in the United States. In 2012, hospitals in the United States ranked first (US News&World Report). In 1846, the first anesthetic operation was performed in human history, and X-ray was first used in clinical practice in 1896. Massachusetts General Hospital dominates the largest hospital based research project in the United States, with an annual research funding of more than 600 million dollars. So far, 13 Nobel laureates have been produced