Although Mayo Clinic in America is called "Clinic", it is actually a comprehensive medical center with a long history. Mayo's history can be traced back to the middle of19th century. 1864, Dr. Mayo set up a clinic in Rochester, Minnesota, mainly to treat the wounded in the American Civil War. After the war, Dr. Mayo's two sons followed in their father's footsteps and cooperated with a local convent to expand the clinic. Since the beginning of the 20th century, Mayo Clinic has gradually established a new medical management model, medical concepts and treatment methods, and has become a multi-disciplinary cooperative hospital, and established a training system for residents (doctors specializing in ward work). Today, Mayo Clinic has other branches in Florida and Arizona, and has its own medical school and dozens of medical clinics covering several neighboring states. At present, there are more than 2,700 clinical experts and scientists.