Boxing legend Muhammad Ali, who had been battling Parkinson's disease for decades, passed away on Friday in a hospital in Phoenix, Arizona, where he had been admitted earlier this week suffering from respiratory problems.

"After a 32-year battle with Parkinson's disease, Muhammad Ali has passed away at the age of 74," spokesman Bob Gunnell said.

Ali was remembered in tributes worldwide for his iconic fight for social justice as well as his legendary boxing battles. The fight against Sonny Liston gave birth to Ali - the legend. Cassius Clay, as he was known then, had just beaten world champion Liston when he turned his wrath on the ringside reporters who had written him off as an underdog, shouting: "Eat your words!"

Here are the three fights that defined the career of Ali:

Clay wins first world title against Sonny Liston

> Watch the video here

Ali beats Foreman in 'Rumble in the Jungle'

> Watch the video here

Ali outlasts Frazier in 'Thrilla in Manila'

> Watch the video here