At the battle of Antietam Confederate General Robert E Lee

 McClellan lets Confederates retreat from Antietam. Confederate General Robert E. Lee's army pulls away from Antietam Creek, near Sharpsburg, Maryland, and heads back to Virginia. ... His army had its back to the Potomac River, just a few miles away, and a quarter of his force had been lost in the previous day's battle.

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thurgood marshall

explanation: in 1954, thurgood marshall and a team of naacp attorneys won brown v. board of education of topeka, kansas. in this landmark decision, the supreme court held that segregation in public education violated the equal protection clause of the fourteenth amendment.