Tens of thousands of people have lined the streets of Muhammad Ali's home city for a funeral procession to say a final farewell to "the greatest".
Chants of "Ali! Ali!" were heard along the 19-mile route as the hearse travelled across Louisville, Kentucky to honour the boxing great.
The casket, covered in a cloth bearing Arabic writing, was placed into the hearse by pallbearers, who included Hollywood star Will Smith and former boxers Lennox Lewis and Mike Tyson, before it left the funeral home.
The procession then travelled along Muhammad Ali Boulevard, passing the Muhammad Ali Centre and his childhood home as fans threw flowers towards the vehicle carrying Ali's body.
As huge crowds waited in sweltering heat for the procession to pass, some of Ali's family and friends in the cars following the hearse waved to people watching from the roadside.
The procession ended at Cave Hill Cemetery, where a private burial took place.
Fans from around the world travelled to Louisville to honour Ali.
Murad Qureshi said he and and his brother-in-law Adam Shabbir made the 4,000-mile trip from London to pay respects to "The Greatest".
He told the Press Association: "I remember when my father passed away, I said the only other funeral I would want to be at would be Muhammad Ali's one.
"Very simply, he's the greatest. He's had a phenomenal influence on a lot of our lives - not just in the sporting arena as the world heavyweight champion three times, but also as a civil rights campaigner and a conscientious objector."
Up to 18,000 people are expected to attend a huge public memorial at the KFC Yum! Centre, with the ceremony broadcast to millions of viewers around the world.
Former US president Bill Clinton will deliver the eulogy, while Ali's widow Lonnie and two of his nine children, daughters Rasheda and Maryum, will also address the congregation.
Speaking ahead of the funeral, former world heavyweight boxing champion Lewis said it was a "privilege" and an "honour" to be involved in the ceremony.
He said: "We're laying to rest another king - the greatest.
"He was the only one that floated like a butterfly and stung like a bee. I think he's in a better place right now."
US president Barack Obama, who missed the funeral to attend his daughter Malia's high school graduation ceremony, described Ali as "an icon" and a "personal hero" who transformed "not just the world of sport, but the world as a whole".
In a video message, he said: "It's very rare when a figure captures the imagination of the entire world. It's even rarer when that figure does so by being open and funny and generous and courageous.
"He was one of a kind. In my book, he'll always be the greatest."
Obama and his wife Michelle sent a letter to be read at the service, where White House senior adviser Valerie Jarrett - who knew Ali personally - will represent the president.
American actor Billy Crystal and Malcolm X's daughter Attallah Shabazz will speak at the funeral, while King Abdullah II of Jordan is expected to be among the congregation.
It was reported Turkish president Recep Tayyip Erdogan, who has been in Louisville and was expected to attend the funeral, had cut short his visit amid claims of a rift with the ceremony's organisers.
Erdogan was initially due to address the funeral but was later removed from the list of speakers after other names were added.
The pallbearers included Jerry Ellis - the brother of Jimmy Ellis, Ali's former sparring partner and fellow world heavyweight champion - and Ali's cousins John Grady and Jan Wadell, nephew Ibn Ali, former brother-in-law Komawi Ali and family friend John Ramsey.
The funeral will be live-streamed on the internet and is also being shown at London's 02 Arena, the site of his 'I Am The Greatest' exhibition.
Some ticket-holders for the funeral have been criticised for trying to profit from the free event by selling tickets online.
Ali family spokesman Bob Gunnell said he was "personally disgusted" at attempts to profit from Ali's funeral and urged people not to buy the tickets.
A traditional Islamic prayer service was held for Ali on Thursday at Freedom Hall, where Ali made his professional debut with victory over Tunney Hunsaker in 1960.