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When did Johnny Cash start performing?
Johnny Cash began performing concerts at prisons in the late 1950s. He played his first famous prison concert on January 1, 1958.
Where was Johnny Cash's first famous prison concert?
Johnny Cash played his first famous prison concert on January 1, 1958, at San Quentin State Prison.
Why did Johnny Cash perform at prisons?
Never serving hard time himself, Johnny Cash had an affinity for the downtrodden. He received letters from inmates around the country asking him to play Folsom Prison Blues.“
What was Johnny Cash's best performance?

Question: What were the names of his two live albums recorded in prison?
Self-contained rewrite: What were the names of Johnny Cash's two live albums recorded in prison?