Floyd Mayweather, Jr.

Floyd Mayweather became a professional boxer in 1996. He had won three national Golden Gloves and an Olympic bronze medal later in the year. By 2007, he was considered the best pound-for-pound fighter in the world with 38 undefeated bouts. He retired in 2008, but he has since returned to the ring.

Widely considered the greatest boxer of his era, Floyd Mayweather Jr. had boxing in his blood. His father, Floyd Sr., was a welterweight contender, and his uncle Jeff Mayweather was an IBO super featherweight champion. Another uncle, Roger Mayweather, is a former World Boxing Council super-lightweight champion.

His father introduced Mayweather to the gym not long after he started walking, holding his young boy in front of speed bags whenever they visited. Soon, Mayweather was throwing punches at anything that came in his view. At age 7 he was fitted for his first pair of boxing gloves. Growing up in a dysfunctional family, Mayweather found peace and control in the ring.

As a pro with his father serving as both manager and trainer, he won several easy bouts during his first two years, which he capped off by capturing his first world title, the WBC junior lightweight championship. His career greatly accelerated even more beginning in 2000, when Mayweather embarked on a seven-year stretch that had many fight fans talking about him as one of the sport's all-time greats.

During this period, he moved up in weight class four times, taking home Ring magazine and WBC lightweight titles in 2001, the WBC super lightweight title in 2005, and Ring magazine and WBC welterweight titles in 2006. In 2007 he defeated Oscar De La Hoya for the WBC super welterweight crown. In the buildup to his much-anticipated match with De La Hoya, Mayweather took center stage in the four-part HBO documentary "24/7," which led to new pay-per-view and live-gate records. Later that year he appeared as a contestant on ABC's "Dancing with the Stars."

In 2007, Mayweather stunned the sports world when he announced his retirement. He returned in September 2009 and won a bout against Juan Manuel Marquez by unanimous decision. Eight months later, he won a 12-round unanimous decision over Shane Mosley in Las Vegas to up his professional record to 41-0.

In May 2013, Mayweather made headlines when he won a 12-round bout against Robert Guerrero in a unanimous decision at the MGM Grand Garden Arena in Las Vegas, taking the WBC welterweight title. The fight bumped Mayweather's record to an undefeated 44-0 (with 26 KOs).