Final answer:
In 1890, Louisiana passed a law requiring separate but equal accommodations on railroads, marking a significant step in the establishment of state-sanctioned segregation laws known as Jim Crow laws.
Step-by-step explanation:
In the context of civil rights, the year 1890 was significant due to the enactment of segregation laws by Southern states, a period often referred to as the Jim Crow era. For instance, in 1890 specifically, the State of Louisiana passed a law that required railroads to provide "equal but separate accommodations for the white and colored races." This institutionalized the practice of segregation and began a long period of entrenched racial discrimination sanctioned by state law. This event marked an escalation in the codification of racial segregation, setting a precedent that culminated in the Supreme Court's Plessy v. Ferguson decision in 1896 which upheld the legality of 'separate but equal' facilities and further solidified segregation as a legally supported system in the United States.