Question: are there any undefeated boxers?
Answer: Round One: László Papp. Although Papp's boxing career might have been relatively short, boy did he make the most of it! ... 
Round Two: Ricardo López. ... 
Round Three: Edwin Valero. ... 
Round Four: Joe Calzaghe. ... 
Round Five: Rocky Marciano. ... 
Round Six: Floyd Mayweather.