Muhammad Ali was a genuine icon of the 20th century. At an early age he identified himself as “The Greatest” and backed up his words inside and out of the boxing ring.

On Sunday, PBS airs part one of “Muhammad Ali,” a sweeping new four-part documentary on the life and cultural impact of Ali.

We discuss the project with filmmaker Ken Burns, and Donald Lassere of the Chicago History Museum, who for years was president and CEO of the Muhammad Ali Center in Louisville, Kentucky.