Today in history: On May 17, 1954, a unanimous U.S. Supreme Court handed down its Brown v. Board of Education of Topeka decision, which held that racially segregated public schools were inherently unequal and therefore unconstitutional. Also on this date: In 1792, the Buttonwood Agreement, a document codifying rules for securities trading, was signed by 24 New York stockbrokers, marking the formation of the New York Stock Exchange. In 1875, the first Kentucky Derby was held; the race was won by