The landmark Supreme Court decision in Brown v. Board of Education, decided in 1954, was significant because it declared state laws establishing racial segregation in public schools unconstitutional. The ruling overturned the precedent set by Plessy v. Ferguson in 1896, which upheld the "separate but equal" doctrine. This monumental decision was a catalyst for the Civil Rights Movement in the United States, emphasizing the principle that separate educational facilities are inherently unequal and damaging to minority children. By promoting desegregation, Brown v. Board of Education played a crucial role in the fight for equality and civil rights across the nation.