Floyd Mayweather Discussing MMA Career With UFC’s Dana White

Floyd Mayweather Jr. (R) throws a punch at Conor McGregor during their super welterweight boxing match on Aug. 26, 2017, at T-Mobile Arena in Las Vegas, Nevada. Sean M. Haffey/Getty Images

As a boxer, he was undefeated—finishing his career at 49–0—matching the record of the legendary Rocky Marciano.

He won and held 15 world titles in five different weight classes.