In case you are not familiar with his history, Floyd Mayweather Jr. has an undefeated record of 47-0, with 26 of those wins coming by way of knockout. He’s had a long, impressive career. Once known as the “Pretty Boy”, he has come a long way in proving that he is one of the greatest boxer's to ever live. Lets take a look at some of Floyd Mayweather Jr.'s greatest knockouts.