Muhammad Ali, the silver-tongued boxer and civil rights champion who famously proclaimed himself "The Greatest" and then spent a lifetime living up to the billing, is dead. Ali died Friday at a Phoenix-area hospital, where he had spent the past few days being treated for respiratory complications, a family spokesman confirmed to NBC News. He was 74. After a 32-year battle with Parkinson's disease, Muhammad Ali has passed away at the age of 74. The three-time World Heavyweight Champion boxer died this evening," Bob Gunnell, a family spokesman, told NBC News.