The first National League “home run” ever hit was by Ross Barnes of the Chicago White Stockings (now the Chicago Cubs) in 1876—the term “run” being literal. In the early days of baseball, ballparks had much larger outfields than exist today and most home runs were in-the-park. A home run where the ball flew over the fence entirely was a rare thing.
Today, home runs come included as part of the standard baseball package. Infields are shorter, hitters are stronger, and, thanks to the prohibition of pitches like the spitball, the baseballs themselves are livelier. Though some of the names on this should come with an asterisk, here are the top 20 home run hitters in Major League Baseball history.