It takes a certain type of person to step into a boxing ring and risk one's own life, and that of an opponent, for the sake of entertainment. It is no wonder then that the sport is full of remarkable characters - and many have gone on to find infamy. Often their life stories are full of brutality and tragedy, with their careers inside the ring mirroring the personal turmoil outside of it. These are the boxers who will be remembered among the most notorious of all.
The unmistakable Mike Tyson's life has been filled with controversy, in and out of the ring
Venezuelan-born Valero perhaps should have never boxed. He was involved in a motorbike accident in 2002 and wasn't wearing a helmet; he fractured his skull and needed surgery to remove a blood clot.
As a result, he struggled to gain a license in the US but fought 27 times overall and won every single one by knockout, becoming WBA super featherweight champion and holding the WBC lightweight title. But such aggression did not stay inside the ropes.
In September 2009, he was arrested for assaulting his sister and mother in a family feud in Venezuela but his mother later insisted there was no violence involved.
Six months later he was accused of assault again, by his wife. She needed hospital treatment for a damaged lung but, despite being treated for similar injuries before, later changed her tune to say she had fallen on stairs. Upon visiting her, Valero threatened the medics and his temper was so wild, he was ordered by a Venezuelan court to enter rehab and attend anger-management classes.
A month later, his wife was found stabbed to death and Valero was arrested, where he reportedly admitted to the murder. A day later, he was found hanged in his prison cell.
'I asked the authorities not to let him out. He needed a lot of help. He was very bad in the head,' his manager Jose Castillo told reporters. 'But they let him out. They were very permissive with him and because of that, we're now in the middle of this tragedy.'
Edwin Valero (left) lands a punch on Antonio DeMarco during his win in February 2010.
The Venezuelan was an aggressive fighter and became a super featherweight world champion - but he was arrested for the murder of his wife and later killed himself while in prison
At the age of 20, Charles 'Sonny' Liston was sent to prison for five-and-a-half years at the Missouri State Penitentiary for armed robbery.
He endured a tough upbringing - the 24th of 25 children in a household so poor that he was sent to work at the age of eight. He claimed not to know what year he was born while his father, Liston said, only ever gave him a beating.
It was behind bars that he was introduced to boxing, with Reverend Alois Stevens suggesting he entered the ring for a sparring session with heavyweight Thurman Wilson.
It lasted two rounds. 'Get me out of this ring,' Wilson is alleged to have said. 'He is going to kill me!'.
Sonny Liston overcame a tough childhood to leave a big mark on heavyweight boxing history
Liston turned professional in 1953 and went on to have a remarkable career, becoming heavyweight champion of the world in 1962 with a first-round knockout of Floyd Patterson, a feat he repeated a year later.
His career was punctuated by run-ins with police. In 1956, he reacted to being stopped on the street by punching a policeman and stealing his gun, for which he served nine months inside.
But he made it back out, and made it back to the ring. Most famously he was beaten by Cassius Clay (Muhammad Ali) in 1964. They had a rematch a year later and Ali knocked him out in the first round.
Liston's death, in December 1970, is shrouded in mystery. He was reportedly discovered near a balloon with heroin in it, and his arm covered in needle marks. Yet he apparently had a fear of needles and in 2013, a man came forward claiming to be the son of the mafia hit-man who killed him.
Liston lands a heavy right hand on the jaw of Muhammad Ali - then Cassius Clay - in 1965
He was a brutal puncher but his own KO by Ali gave boxing one of its most famous pictures
'I was Mike Tyson before Mike Tyson came along,' Duran wrote in his autobiography. 'Fighters would take one look at me and crap in their pants. "El Diablo", they called me: "The Devil".'
Duran was a brutal lightweight, arguably the best and most dangerous in boxing's history, and moved up to welterweight, light middleweight and middleweight, winning titles in each.
Duran loved fighting. He didn't retire until he was 50 years old, in 2002. He fought a total of 119 times, winning 103 with 70 coming via a knockout.
His most famous fights were his three against Sugar Ray Leonard. Duran won the first in Canada in 1980 but was defeated the next two times, the rematch later that year renowned in boxing history as the 'no mas' bout.
The match was ended in the final moments of the eighth because Duran apparently said 'no mas' to referee Octavio Meyran - which means 'no more' in Spanish. Duran insisted he never said he wanted to quit and was taunted by Leonard post fight.
'I made him quit', Leonard said. 'To make Roberto Duran quit, was better than knocking him out.'
Duran later said he quit because he was struggling with stomach cramps, but even his manager rejected that and said it was because he was losing the fight so dramatically.
Duran lost the decider in 1989.
Roberto Duran (right) cracks the jaw of Iran Barkley during a fight in Atlantic City in 1989
His fighting style was ultra-aggressive and he earned the nickname 'The Devil'
He had famous fights against Marvin Hagler (above), Sugar Ray Leonard and Tommy Hearns
There was nothing like Mike Tyson when he burst onto the heavyweight scene in 1985 at the age of 18. Tyson was boxing's youngest ever heavyweight champion at 20 when he defeated Trevor Berbick. He won 26 of his first 28 fights by knockout and out of his 50 career wins 44 were by KO.
His aggression, his speed and his power left opponents scared of Tyson before they even entered the ring - look at his fight with Michael Spinks in 1988.
Yet his nickname 'The Baddest Man on the Planet' wasn't just because of how powerful he was in the ring.
Tyson infamously bit part of Evander Holyfield's ear off in the third round of their 1997 rematch. He was disqualified, having already been deducted two points for biting Holyfield's other ear. Tyson claimed his action was a retaliation to Holyfield repeatedly headbutting him without being sanctioned.
Away from boxing, Tyson was sent to prison in 1992 for six years after being found guilty of rape. He served three years and was released in March 1995. Tyson converted to Islam during his time in prison.
It was during his time in prison that Tyson discovered a way to own a tiger.
He explained on Joe Rogan's podcast in January: 'So I'm in prison, I’m talking to my car dealer at the time and he has some cars that belong to a [mutual friend], and he’s discussing, "If he doesn’t pay for these cars, I’m going to sell these cars to somebody and get some horses."'
“I said, "What, you can get horses? And trade horses in for cars?" Because I had a lot of cars, I’d probably get some horses too. And he said, "Yeah man, you can get cougars, lions, tigers…" I said, "You do?! Can you get me some tigers?"
'And I’m a young guy. I’m saying to myself, "Wow, that would be cool. Get me some cubs, man".'
Tyson knocks out Trevor Berbick to become youngest heavyweight world champion in history
His behaviour out of the ring was often odd - such as owning a pet tiger - and sometimes awful
His infamy inside the ring was sealed when he bit a chunk out of Evander Holyfield's ear
Mexican-American boxer Antonio Margarito lost his license in 2009 when his hand wraps failed a pre-match inspection before his fight with Shane Mosley.
They contained gypsum, a chemical which, when combined with sweat or moisture, forms plaster that is used to make casts. At a hearing, Margarito insisted he did not know what was in his wraps and it had been an error by his trainer, Javier Capetillo.
Later that year, the LA Times said stains on Margarito's
