This campaign started in Greensboro, Alabama on the 1 February 1960.
Four black students, Franklin McCain, Joseph McNeil, Edzell Blair and David Richmond ordered food at a white people only lunch counter. The four students were refused service.
When asked to move they refused and returned to the same lunch counter the next day with dozens more protesters, some of whom were white.
The idea of sit-ins spread quickly, by the start of 1961 it was estimated that around 700,000 people had taken part.
News of the sit-ins was broadcast throughout America on television, gaining the civil right movement publicity.
Many white people also showed solidarity with the black protesters and joined the sit-ins. Dozens of lunch counters in the South were desegregated by the summer of 1960.