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Jack Dempsey

1919-26

A cultural icon of the 1920s, "The Manassa Mauler" held the heavyweight championship for seven years and is renowned as one of the most devastating punchers in history. Dempsey, despite a glaring size disadvantage, won the title by third-round TKO over Jess Willard in 1919, dropping the giant seven times in the first round.

Dempsey famously got up after being knocked through the ring ropes to knock out another titan, Luis Angel Firpo, in 1923. But after a three-year hiatus, Dempsey lost the title to Gene Tunney on points in 1926. In the rematch a year later -- the famous "Long Count Fight" -- Dempsey refused to go to a neutral corner after knocking Tunney down, allowing Tunney extra time to recover and win.