Muhammad Ali at 70: Life In Pictures

He is one of the most recognised figures of all time and as he celebrates his 70th birthday boxing legend Muhammad Ali is ''still the greatest'' to friends and admirers worldwide.

As the celebrations in honour of his 17 January birthday got under way, the three-time World Heavyweight champion had a lot to celebrate.

At the tender age of 12, Cassius Clay, as he was then called, took up boxing at a local gym after his bike was stolen and he wanted to find and "whip" the culprit.

The young boy that was introduced to boxing coach Joe Martin would go on to change his name to Muhammad Ali and become one of the best boxers who ever lived.

In his 20-year career, Ali won 56 fights and scored 37 knock-outs. Even after he retired he continued his humanitarian efforts by becoming a powerful activist for black rights in the US and around the world.

Ali was the first man to win the heavyweight title of the world three times. He won the BBC's Sports Personality of the Century award in 1999.

Not only is he celebrated for mastering his craft he has also been recognised for his humanitarian efforts, despite being diagnosed with Parkinson's disease in the 1970s.

While hundreds of fans and supporters belted out a heartwarming rendition of ''Happy Birthday'' during a private party held in Louisville, Kentucky, where he was born, the boxing icon basked in the love.

Lennox Lewis led the tributes, describing Ali as "still the greatest". Former boxing rival George Foreman said he was "a prophet, a hero, a revolutionary" in a another touching tribute.