Picking the best boxer of all time is mighty difficult.
The main issue is the plethora of weight divisions within the sport. How can you really compare a heavyweight specialising in knockouts with a highly-skilled welterweight that breaks opponents down over 12 rounds?
You can't really, but that doesn't mean boxing fans will ever stop trying to rank the greatest fighters of all time.
In lists of this fashion, the most common names to feature are the likes of Muhammad Ali, Mike Tyson and Floyd Mayweather.
Well, over on TheTopTens, that trio predictably feature on the website's list asking fans to pick the greatest to have partaken in the sport over the years.
Below, we've provided the top 15 names selected in order, along with some of the best comments from users.
15. Marvin Hagler
"One of the greatest middleweights of all time, Mayweather wouldn't stand a chance."
14. Jack Johnson
"No one at any weight could take Johnson in his prime. His defense was an art form that no one else could master."
13. Willie Pep
"Watch a Willie Pep highlight then tell me he is not the slickest boxer of all time."
12. George Foreman
"This man dominated two eras of boxing, by the way the two best eras."
11. Roberto Duran
"Just The Greatest. He was far better than Ray Leonard, who admitted he was the hardest puncher he ever faced and that he was also the hardest boxer to hit cleanly."
10. Roy Jones Jr.
"I feel like everyone over looks Roy. In his prime I don't think anyone could have beaten him. So much speed and power."
9. Henry Armstrong
"No one in that history of boxing has accomplished what Hammering Henry was able to."
8. Floyd Mayweather Jr.
"This guy has been hated on nearly his whole career. Everyone they put in front of him, they say he would lose to, he beat."
7. Sugar Ray Leonard
"Leonard was one of the most versatile boxers the game has ever seen."
6. Joe Louis
"This man is simply the greatest, watching him fight in his prime...no-one ever stood a chance."
5. Rocky Marciano
"He is the greatest of all time and he also has the greatest single punch of all time."
4. Manny Pacquiao
"Eight championship belts. Enough said."
3. Mike Tyson
"Deadly combination of speed and power to knock anyone out."
2. Sugar Ray Robinson
"Ali said he was the GOAT, that's how good he was. One of the greatest pound for pound boxers ever."
1. Muhammad Ali
"5 losses, over 50 wins... He was an iconic figure who had a substantial name for himself. Unbeatable."
GIVEMESPORT'S Danny Ryan says...
Ali is a worthy winner here, but are we really going to kid ourselves that Tyson deserves to be third?
The guy may be the youngest heavyweight champion in history, but the level of opponent he defeated throughout his career pales in comparison to others on this list.
In truth, the likes of Lennox Lewis and Evander Holyfield both deserve to be on this list ahead of 'Iron Mike'.
Pacquiao over Mayweather is also an eyebrow raiser, given how the latter dominated proceedings when they met in the ring.
You get the feeling 'The Money Man's' divisive reputation has cost him a couple of places.