Answer
Luc Montagnier discovered the Human Immunodeficiency Virus, or HIV, which causes AIDS. Montagnier was a French virologist who conducted research at the Pasteur Institute in Paris. In 1983, he and Françoise Barré-Sinoussi published a paper in which they identified a new virus that they believed to be the cause of AIDS. This discovery was later confirmed by other researchers, and HIV is now recognized as the cause of AIDS.