Homer Plessy looked like an average white man, but he was part of a conspiracy to challenge Jim Crow laws that relegated black people to second-class citizen status. Once he was seated with his first-class train ticket that day in June of 1892, he told the conductor that he was one-eighth black!
It worked! The US Supreme Court heard the case in 1896, but it upheld that the Louisiana law segregating black people from white people was Constitutional provided there were "separate but equal" accommodations.
It was a devastating blow to African American freedom and education; one from which there would be several milestones reached by many, many stepping stones.