Which case did Brown v Board of Education overturn?

The answer to this is that the Brown
case overturned a case called Plessy v. Ferguson.  This case was
decided in 1896.

The Plessy decision
was the one in which the Supreme Court laid out the doctrine that "separate but equal"
facilities for people of different races did not violate the 14th Amendment.  The Court
argued that the 14th Amendment said that blacks and whites had to be treated equally,
but not that they had to be treated equally in the same train cars.  So long as the
train cars (or, by extension, the schools) were equal, the fact that they were separate
was not important.

In Brown, the Court
held that separate schools for the races were inherently unequal.  By making this
ruling, it effective overruled Plessy.