Final answer:
The Tuskegee Syphilis Study was one of the longest running unethical research projects in history, lasting from 1932 to 1972. It involved African-American men who were diagnosed with syphilis but were not informed or treated for the disease. The study aimed to observe the impact of untreated syphilis on Black men.
Step-by-step explanation:
The longest running unethical research project is known as the Tuskegee Syphilis Study. The study was conducted from 1932 to 1972 by the U.S. Public Health Service, and it involved 399 African-American men who were diagnosed with syphilis but were never informed about their condition or given appropriate treatment. The study aimed to understand the impact of untreated syphilis on Black men, and even when treatment for syphilis became available, the researchers intentionally withheld it from the participants.