Antwerp, 1920: In a 30-minute span, American Jack Kelly rowed to victories in the single and double sculls. Kelly added a third gold in 1924. Five years later, he had a daughter, Grace, who starred in such Hitchcock classics as "Dial M for Murder," "Rear Window" and "To Catch a Thief" before becoming the Princess of Monaco. Jack's son, John Kelly Jr., also took to the water, rowing at four Olympics.
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http://universalsports.nbcsports.com/articles/inside_sport/189?sport_id=17
Paris, 1924: The U.S. men's eight won gold in Paris by nearly 16 seconds ahead of the Canadians. In the American boat was Benjamin Spock, who became a pediatrician and in 1945 authored "The Common Sense Book of Baby and Child Care," which sold more than 45 million copies.
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Melbourne, 1956: American John Kelly Jr., the brother of Grace Kelly and son of three-time Olympic rowing champion Jack Kelly, won bronze in the Melbourne single sculls event. Although he never matched his father's Olympic success, Junior was an accomplished rower in his own right, twice winning the prestigious Henley Royal Regatta in England.