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Twitter 上的ESPN Ringside:"On this date in 1956, Rocky Marciano announced his retirement from boxing with a perfect 49-0 record. He remains the only heavyweight champ to finish his career undefeated. https://t.co/sIZYYDh7QQ" /
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Floyd Mayweather equals 49-0 record with unanimous decision victory over Andre Berto - Sport360 News
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10 amazing boxers with the longest winning streaks, including Julio Cesar Chavez, Roberto Duran and Floyd Mayweather Jr
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Column: Floyd Mayweather, Rocky Marciano and why 48, 49 and 50-0 have little significance - mlive.com
![MMA History Today en Twitter: "Apr27.1956 Legendary Boxer Rocky Marciano Announces his Retirement from Boxing He retired with a Record of 49-0 http://t.co/uV2jssrbs6" / Twitter MMA History Today en Twitter: "Apr27.1956 Legendary Boxer Rocky Marciano Announces his Retirement from Boxing He retired with a Record of 49-0 http://t.co/uV2jssrbs6" / Twitter](https://pbs.twimg.com/media/BmQxckYCIAAS5w-.jpg)
MMA History Today en Twitter: "Apr27.1956 Legendary Boxer Rocky Marciano Announces his Retirement from Boxing He retired with a Record of 49-0 http://t.co/uV2jssrbs6" / Twitter
![Rocky Marciano's legendary 49-0 record: For it to be truly broken, must it be a reigning heavyweight champion who reaches 50-0? Rocky Marciano's legendary 49-0 record: For it to be truly broken, must it be a reigning heavyweight champion who reaches 50-0?](https://www.boxing247.com/wp-content/uploads/2017/04/marciano423.jpg)