In 1932, the United States Public Health Service, or USPHS, began the Tuskegee Syphilis Study, initially known as the Tuskegee Study of Untreated Syphilis in the Negro Male, as an experiment to understand the effects of untreated syphilis in Black men. When the study began, there was no known cure for syphilis. The study involved 600 Black men in Macon County, Alabama, and took place on the campus of Tuskegee Institute, now Tuskegee University. The study leaders did not tell the men the truth about the purposes, risks, or benefits of the study. Moreover, despite the development of an effective drug against syphilis—penicillin, available beginning in the late 1940s—the study investigators withheld treatment and continued to examine the untreated progression of the disease in the men. The study went on for forty years. The US government officially shut it down in 1972 after information about the study leaked to the public. The researchers’ unethical practices, including not obtaining informed consent from the participants, led to changes in federal laws regarding human clinical trials and to the creation of the Belmont Report, which outlines ethical human research guidelines.