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STORY: The POWs and veterans first took part in parade through Yorba Linda, where they were greeted by hundreds of cheering supporters waving U.S. flags along the parade route. Later, an official ceremony took place on the grounds of the library.

"I had absolutely zero doubt that my country would never forget me, that I would be brought home, back to my country whether I was alive or did not survive. That, the strength of having that knowledge, was part of what got me through six and a half years of helL," said Tom McNish, an 82-year-old POW who was captured after he was shot down over North Vietnam on September 4, 1966.

Orson Swindle, an 86-year-old POW, told Reuters: "We all suffered in many, many ways that most people don't know anything about -- you know, family separation and death and just bad circumstances. But we overcame it all."

The Nixon Presidential Library is marking the 50th anniversary of the return of the POWs with a new exhibition, "Captured. Shot Down in Vietnam."