Our colleagues at BBC Sport have all the latest tributes and reaction to the death of Muhammad Ali.
- Boxing legend Muhammad Ali has died, aged 74, a family spokesman has said
- He was admitted to hospital in Phoenix, Arizona, on Thursday with a respiratory illness
- His funeral will take place in his hometown of Louisville, Kentucky
- The former heavyweight champion was diagnosed with Parkinson's Disease in 1984
Hana Ali has also posted photographs of her late father on her Instagram page.
At the 1960 Rome Olympics, Muhammad Ali - then Cassius Clay - won the gold medal for light heavyweight boxing.
When the Olympics came to Atlanta in 1996, Ali - who had been diagnosed with Parkinson's Syndrome in 1984 - was watched by billions around the world as he lit the Olympic cauldron.
Ali, who had thrown his original gold medal into the Ohio River when he was criticised for not fighting in Vietnam, received a replacement medal at the 1996 Atlanta Olympics.
And at the most recent Olympic Games, at London in 2012, Ali made a special appearance to be a flag bearer.
Muhammad Ali appeared on Michael Parkinson's chat show four times.
In this 1974 clip, at the peak of his career, Ali speaks movingly about the reasons why he fights.
Ali turned bragging into an art form, the Los Angeles Times says. "I'm so mean I make medicine sick," he once quipped, and "I'm so fast that last night I turned off the light switch in my hotel room and was in bed before the room was dark."
Hillary and I are saddened by the passing of Muhammad Ali. From the day he claimed the Olympic gold medal in 1960, boxing fans across the world knew they were seeing a blend of beauty and grace, speed and strength that may never be matched again.
We watched him grow from the brash self-confidence of youth and success into a manhood full of religious and political convictions that led him to make tough choices and live with the consequences. Along the way we saw him courageous in the ring, inspiring to the young, compassionate to those in need, and strong and good-humored in bearing the burden of his own health challenges.
I was honored to award him the Presidential Citizens Medal at the White House, to watch him light the Olympic flame, and to forge a friendship with a man who, through triumph and trials, became even greater than his legend. Our hearts go out to Lonnie, his children, and his entire family.
Ali will be remembered as much for his rhymes as boxing, The Washington Post says, which he used to belittle his opponents and embellish his own abilities.
“This is the legend of Cassius Clay, the most beautiful fighter in the world today,” the paper quotes him saying before his 1964 title bout.
“The brash young boxer is something to see, and the heavyweight championship is his destiny.”
The BBC's Joe Wilson takes a look back at the life and career of Muhammad Ali. You can watch the video obituary above.
Ali was the most thrilling if not the best heavyweight ever, The New York Times says, carrying into the ring a physically lyrical, unorthodox boxing style that fused speed, agility and power more seamlessly than that of any fighter before him.
"But he was more than the sum of his athletic gifts," the paper says. "An agile mind, a buoyant personality, a brash self-confidence and an evolving set of personal convictions fostered a magnetism that the ring alone could not contain. He entertained as much with his mouth as with his fists, narrating his life with a patter of inventive doggerel."
Figures from the world of boxing and beyond have been paying tribute to Muhammad Ali since the news of his death at the age of 74 broke earlier this morning.
Don King describes it as a "sad day for life", while Manny Pacquiao says: "We lost a giant today".
We're collating the tributes as they come in - read more here.
From our archive: Former US President Bill Clinton told BBC 5 live in 2011
"The courage Muhammad Ali showed as an older man in later life battling Parkinson's Disease was every bit as great as that showed earlier in his boxing career when he risked having his body, brain and face regularly being battered."
World cruiserweight champion Tony Bellew tells BBC 5 Live:
He was the ultimate hero. It's heartbreaking news to wake up to. The greatest sportsman of all-time in my opinion. He transcended the sport and this is a sad day. I hope something can be named after him. He can never be replicated.
Promoter Eddie Hearn says on Sky Sports News: "Icon is a word that gets bandied around but it's the best word to use to describe Muhammad Ali. He transcended the sport."
He lived and stood for so many things, and was someone who was instantly recognisable. He was a true legend of the sport and after a long period of suffering, he rests in peace now, God willing. It's a really sad day for boxing and he was a man that did so much for the game.
Here are just a few of the many pictures from Ali's incredible career.
Former professional boxer Floyd Mayweather Jr has been paying tribute to Ali on Fox News in the US.
There will never be another Muhammad Ali. The black community all around the world, black people all around the world, needed him. He was the voice for us. He's the voice for me to be where I'm at today.
Kellie Maloney has also been talking on BBC Breakfast.
She said Ali "took boxing from the back pages", adding: "To meet the man was such an honour."
He was a man that in the ring could be brutal... but outside the ring, he had principles and stood by them.
Ali changed his name from Cassius Clay in 1964 and would go on to say: "Cassius Clay is a slave name. I didn't choose it and I don't want it. I am Muhammad Ali, a free name - it means beloved of God, and I insist people use it when people speak to me and of me."
The most famous band in the world met the most famous boxer in 1964 and Beatles drummer Ringo Starr paid his tribute today.
Current promoter Eddie Hearn, who looks after current world champion Anthony Joshua, said: "Waking to the sad news that 'The Greatest' has passed. Rest in peace Muhammad Ali you shook up the World."
Five-division former world champion Floyd Mayweather Jr says: "There will never be another Muhammad Ali. The black community all around the world, black people all around the world, needed him. He was the voice for us. He's the voice for me to be where I'm at today."
Let's look back at some of the legendary quotes from the great man. This is one of the most often quoted, before his famous fight with George Foreman in 1974.
"Float like a butterfly sting like a bee - his hands can't hit what his eyes can't see."
BBC Radio 5 Live
Promoter Kellie Maloney tells BBC Radio 5 Live: "If you asked my daughters who the favourite sportsman in the world is, they'd say Muhammad Ali. He didn't just win battles in the ring, he won battles outside of the ring.
"He could hold a room. Even when he wasn't well, people were in awe of him."
- Won Olympic light-heavyweight gold in 1960
- Turned professional that year and was world heavyweight champion from 1964 to 1967, 1974 to 1978 and 1978 to 1979
- Had 61 professional bouts, winning 56 (37 knockouts, 19 decisions), and losing five (4 decisions, 1 retirement)
Manny Pacquiao, the former world champion and current politician, said in a statement: "We lost a giant today. Boxing benefited from Muhammad Ali's many talents but not nearly as much as mankind benefited from his humanity."
Barry McGuigan, former world featherweight champion, told BBC Breakfast he felt "sadness, because of how great a human being he was and what he's done for boxing".
He was just the greatest sportsman that has ever been and we are very lucky that he happened to be involved in our sport. He was a very special man.
He described Ali as an "amazing humanitarian" and "hugely talented man" who was also incredibly humble and "brilliantly charismatic".
McGuigan added: "He inspired millions of people".