In baseball, the "Shot Heard 'Round the World" was a walk-off home run hit by New York Giants outfielder and third baseman Bobby Thomson off Brooklyn Dodgers pitcher Ralph Branca at the Polo Grounds in New York City on October 3, 1951, to win the National League (NL) pennant. Thomson's dramatic three-run homer came in the ninth inning of the decisive third game of a three-game playoff for the pennant in which the Giants trailed 4–1 entering the ninth and 4–2 with two runners on base at the time of Thomson's at-bat.

Robert Brown Thomson was a Scottish-born American professional baseball player, nicknamed "the Staten Island Scot". He was an outfielder and right-handed batter for the New York Giants, Milwaukee Braves (1954–57), Chicago Cubs (1958–59), Boston Red Sox (1960), and Baltimore Orioles (1960). His pennant-winning three-run home run for the Giants in 1951 is popularly known as the "Shot Heard 'Round the World", and is one of the most famous moments in baseball history. It overshadowed his other accomplishments, including eight 20-home-run seasons and three All-Star selections. "It was the best thing that ever happened to me", he said. "It may have been the best thing that ever happened to anybody."