"He's still the greatest," Lewis said. "He's not just the greatest in the ring. You look at what he's done outside the ring, his bravery, poise and sacrifice -- he's truly a great man."
Lewis wasn't alone in his accolades. A 350-person guest list that included politicians and stars from the entertainment and sports worlds paid tribute to Ali at the $1,000-per-plate benefit for the Muhammad Ali Center.
"I know a good humanitarian when I see one," said Ann Curry, co-host of NBC's "Today" show. "He has changed the world, made children less hungry and people more equal. Those are the things that make you immortal."
Ali himself greeted the crowd flanked by an entourage of family and pals, The (Louisville, Ky.) Courier-Journal said. The guests sang "Happy Birthday" and broke out in the familiar "Ali" chant before heading into the Ali Center banquet room.
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