Homer Plessy, a Creole man one-eighth African American, boarded a whites-only railroad car. Much like Rosa Parks, Plessy did so as part of an organized effort to challenge the Constitutionality of official segregation. The litigation, Plessy v. Ferguson, reached the United States Supreme Court, which had become more segregationist as the case progressed through the court system. In its 1896 decision, the Court created the "separate but equal" doctrine, which allowed segregation as long as the accommodations provided met the aforementioned test. The decision was overruled in 1954 in Brown v. Board of Education, which held that separate is inherently unequal.
The picture is of Plessy's tombstone, which I took during our trip to New Orleans in 2011.