In the mid 80s however, he had a record do poorly (Hearts and Bones) and a marriage that wasn't going well (to Carrie Fisher) and a tape of South African music was the only thing that was cheering him up.
He flew to South Africa to learn more about the music he was listening to and to collaborate with South African musicians. Simon brought his longtime engineer and producer Roy Hallee with him and they recorded a lot of jam sessions without having written any songs ahead of time.
Back in the States, Simon wrote lyrics and melodies to lay over the music
This unorthodox method of composition (not unlike what David Byrne and Brian Eno were doing with the Talking Heads) resulted in Simon's most celebrated album to date, Graceland.
The documentary series "Classic Albums" focused an hour on Graceland, and that can be found (for now) in parts on YouTube, starting with part 1:
Ultimately, Graceland introduced South African culture and art to the world and arguably helped people see beyond the politics to the people. More recently, a new documentary takes a look back at the album for an assessment of it's cultural impact. The film, originally titled "Under African Skies" and later subtitled "Paul Simon's Graceland Journey" came out in 2012 and aired on PBS, so it may show up again. Meanwhile, the trailer still can be found online: