Answer :
"Brown v. Board of Education" was a landmark case because the decision overturned the standing ruling, "B. Plessy v. Ferguson" which endorsed separate but equal facilities.
B."Plessy v. Ferguson"
In the Plessy v. Ferguson Case (1896), the Supreme Court ruled that racially segregated public facilities were legal as long as the facilities for blacks and whites were equal.
Nevertheless, the Brown v. Board of Education Case (1954) proved something different and rendered invalid the decision of the Plessy v. Ferguson Case. It determined that “separate but equal” facilities were in fact, unequal, they were a form of discrimination that instilled a sense of inferiority to African Americans and thus it violated the 14th Amendment, an amendment that guaranteed all citizens equal protection of the laws.