Muhammad Ali, born Cassius Marcellus Clay Jr., was an American professional boxer who became one of the most well-known and respected athletes of the 20th century. His confidence, charisma, and trademark trash talk made him one of the most polarizing figures in sports history. Ali was a three-time heavyweight champion of the world and is often considered one of the greatest boxers of all time. Outside of the ring, he was also known for his activism and involvement in the civil rights movement. His legacy continues to inspire athletes and activists around the world.