The Central Maine Youth Center in Lewiston set for the historic rematch between Muhammad Al and Sonny Liston. In this photo, boxers fight a the preliminary bout the night of May 25, 1965. Photo from the archive of the Evening Express

Heavyweight champion Muhammad Ali is momentarily displeased after weigh-in ceremony, May 25, 1965 in Lewiston, Maine, arena. Challenger Sonny Liston will be the object of Ali?s more potent attentions in 15-round title bout tonight. Liston weighed 215 ¼ and Clay 206. The Associated Press

Former Heavyweight Champion Sonny Liston shows the press his hammer-hard fist, but it was his glass chin on the night of May 25, 1965 at the Central Maine Youth Center in Lewiston that sent him to the canvas from the "phantom punch" thrown by Muhammad Ali in the first round. Photo from the archive of the Maine Sunday Telegram.

Perspiration beads the face of world heavyweight boxing champion Muhammad Ali shown in training for his May 25, 1965 fight with Sonny Liston at Lewiston. The Associated Press

Former Heavyweight Champion Sonny Liston. Photo from the archive of the Maine Sunday Telegram

Dignitaries, including singer Robert Goulet (center), former Heavyweight Champions Joe Lewis (center right) and Floyd Patterson (far right), line up in the ring before the fight at the Central Maine Youth Center, May 25, 1965. Photo from the archive of the Evening Express.

Robert Goulet sings before the bout between Ali and Liston. Photo from the archive of the Evening Express

Fomer Heavyweight Champion Floyd Patterson (center), signs autographs before the fight at the Central Maine Youth Center, May 25, 1965. Photo from the archive of the Evening Express.

Muhammad Ali (right) strikes Sonny Liston with a punch early in the first round of the much-anticipated and controversial rematch at the Central Maine Youth Center in Lewiston May 25, 1965. Photo from the Evening Express archive.

Sonny Liston (right) misses Muhammad Ali with a punch early in the first round of the much-anticipated and controversial rematch at the Central Maine Youth Center in Lewiston May 25, 1965. Photo from the Evening Express archive.

Governor John H. Reed (center) awaits the much-anticipated fight between Sonny Liston and Muhammad Ali. Reed was key in bringing the historic fight to Lewiston when promoters were scrambling at the last minute to find a new venue for the bout after pulling the fight out of Boston. Photo from the archive of the Evening Express

Fans cheer and jeer at the historic rematch between Muhammad Ali and Sonny Liston at the Central Maine Youth Center in Lewiston, May 25, 1965. Photo from the archive of the Evening Express.

Muhammad Al tells the crowd and television audience how he won the fight against former Heavyweight Champion Sonny Liston. Ali knocked Liston out with the "phantom punch" midway through the first round. Photo from the archive of the Evening Express

Ali with his first wife Sonji Roi following his fight with Sonny Liston at the Central Maine Youth Center in Lewiston, May 25, 1965. Photo from the archive of the Evening Express

Ali with his first wife Sonji Roi following his fight with Sonny Liston at the Central Maine Youth Center in Lewiston, May 25, 1965. Photo from the archive of the Evening Express

Odessa Grady (right) wipes lipstick from her son's cheek as Ali hugs his first wife Sonji Roi following his fight with Sonny Liston at the Central Maine Youth Center in Lewiston, May 25, 1965. Photo from the archive of the Evening Express

Muhammad Ali describes the knockout punch that sent former Heavyweight Champion Sonny Liston to the canvas midway through the first round. Photo from the archive of the Evening Express