Top 10 All-Time Greatest Heavyweights

The model of the modern super heavyweight, Lewis fought big, with a good jab and huge right hand. Much of his success came from his learning and adapting throughout his career.

Marciano was the only heavyweight champion to retire undefeated. Seemingly impervious to punishment, the "Brockton Blockbuster" was often outsized, but never outworked.

Relentless, swarming and implacable with that terrible, swift left hook -- there was no place to hide when Joe was Smokin'.

Though inelegant at times, Big George was an irresistible offensive force. In 1987, after a 10-year layoff, he returned older and heavier, but smarter than ever and nearly as effective.

The "Manassa Mauler" was a ferocious attacking force and pound-for-pound the hardest puncher in heavyweight history. Electrifying in action.

The first black heavyweight champion and the first truly modern champion, Johnson had great speed, power in both hands and was a defensive wizard.

His 20 successful title defenses are second only to Louis's 25. With an unmatched jab and tremendous ring smarts, Holmes described his crafty style by saying, "You always got to make somebody drunk before you mug him."

At his peak, Liston was an absolute destroyer (ask Floyd Patterson) and far more complete fighter than he is given credit for.

He was the classic boxer-puncher, and the greatest finisher in heavyweight history.

He's been called "The Greatest" and, you know what? He was. Speed, grace, a transcendent ring intelligence and miraculous resilience made Ali a legend in the ring.