This year, the nephew of one of those escapees will try retracing the route of his uncle.
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It's one of the toughest races around. The goal, escape from the rock, just like convicted bank robbers Frank Morris and brothers, John and Clarence Anglin did in 1962.
"Oh yes, I will definitely escape. They did it. I'll do it," said Ken Widner.
You could say Widner is keeping the family tradition alive by competing in the triathalon. His uncles, the Anglin brothers, made that daring escape, but were never found.
"They made a raft out of 52 raincoats," said brother David Widner
Brother David Widner is there for moral support. The two just visited Alcatraz, standing in the same cell where their uncles did time and dug their way out.
"To see how small those cells are, I wouldn't stayed either," David Widner said.
The ABC7 News I-Team recently shed new light on the escape. A witness said he may have seen a boat near Alcatraz that night, which could have carried the convicts to safety.
"I can tell you from my family's point of view, they made it and we can prove it," said Ken Widner.
Widner says a photo, taken in 1975 proves the brothers made it to Brazil.
The swim on Sunday is a family tribute.
"So, it's a way for me too look back and remember them a litle bit. As far as I know John may watch me do it," Ken Widner said.
Uncle John, the fugitive, a spectator? The mystery continues.