Muhammad Ali, the world's greatest sporting legend, died on Friday, aged 74. He was in hospital in Phoenix, Arizona with breathing problems. His children flew to be with their father for his final days. Many people say Ali is the best boxer in history. He was the world heavyweight champion three times. His nickname is 'The Greatest'. People believe he was the greatest because of what he did outside the boxing ring. He was a civil rights hero and opponent of the Vietnam War. He was also an ambassador for world peace for five decades, and he worked tirelessly for charities.

World leaders and sporting figures have paid tribute to Ali. One said: "Ali transformed this country and impacted the world with his spirit. His legacy will be part of our history for all time." The U.N. Secretary-General said Ali fought for a better world, "and used his platform to lift up humanity". The daughter of Martin Luther King wrote: "You were a champion in so many ways." Ali once said: "I would like to be remembered as a man who won the heavyweight title three times, who was humorous and who treated everyone right [and] tried to unite all humankind through faith and love."