A poster pleading for the release of Nelson Mandela from prison. (Photo via the Nelson Mandela Foundation)

Today we are celebrating Nelson Mandela’s 94th birthday and revisiting our award-winning series Mandela: An Audio History.

Between 2003-2004 we conducted 100 hours of interviews with more than 50 leaders of the struggle against apartheid. We are working with the Nelson Mandela Foundation’s Centre of Memory to archive this historic collection.

Each one of those recordings has a story behind it.  Sometimes, the story is better than the tape.

During the 27 years that Nelson Mandela was in prison, the public never heard his voice. One man who did was Cristo Brand. Brand was one of the prison guards on Robben Island, and over the years he became friendly with Mandela. Brand was given the task of secretly recording and transcribing every prison visit with Mandela and his family. One time Brand brought home one of these cassette tapes to transcribe and forgot to return it to the prison authorities. For two decades, the tape was forgotten in a box in his garage. Brand mentioned the recording when we interviewed him, but it took us months to convince him to let us hear the actual tape. I was excited and nervous the day we arrived to listen  – there were no known recordings of Mandela during his 27 years in prison, and I thought I was on the verge of hearing something extraordinary. One side of the cassette was labeled Christian Rock. I put in side B and hit play. And the sound that came out was…awful. The tape was so old and poorly recorded that it was impossible to understand more than a few of Mandela’s words.

This tape belongs on the Top 10 list of historic – and yet unintelligible – recordings.

It was little more than ambiance. And yet ambiance is pretty important if you happen to be producing a radio documentary and trying recreate the texture of history.

—Joe Richman

@radiodiaries

• Visit our new Mandela website: mandelahistory.org
• Subscribe to the Radio Diaries podcast. This month we’re featuring stories from our series, Mandela: An Audio History.