The Day Bob Dylan Walked the Line with Johnny Cash

When their paths crossed, the two would often engage in backstage duets � even though their voices weren't the most perfect of matches. A couple of these moments were caught on film. Their version of "I'm So Lonesome I Could Cry" can be seen in Martin Scorsese's No Direction Home, and their take on "I Still Miss Someone" is featured in Dylan's unreleased Eat the Document.

But the two wouldn't sit down to formally record a duet until this day in 1969. Following his mid-'60s rock records, his motorcycle accident and the rustic roots inspirations of John Wesley Harding, Dylan had come to Nashville to make a full-blown country record in February of '69. Dylan and some A-list session guys had laid down the bulk of the album's tracks over a couple of days in Columbia Studios. Toward the end of the sessions, on February 17, Cash stopped by to say hello, and to take a break from recording his own album.

"I had microphones set up and stools and tapes and everything" producer Bob Johnston later remembered. "They looked at each other... got their guitars and started playing."