Here's a look at some of his most famous quotes and moments.
- "Float like a butterfly, sting like a bee."
- "He who is not courageous enough to take risks will accomplish nothing in life."
- "The man who views the world at 50 the same as he did at 20 has wasted 30 years of his life."
- "Service to others is the rent you pay here on earth."
- "I am the greatest, I said that even before I knew I was."
- "The man who has no imagination has no wings."
- "I know where I'm going to be and I know the truth, and I don't have to be what you want me to be. I'm free to be what I want."
- "It isn't the mountains ahead to climb that wear you out; it's the pebble in your shoe."