When Masekela was recording an album in 1968, he needed one more song to fill it out. The record company suggested a tune called "Mr. Bull #5" that Masekela had heard on the radio while growing up in Africa.
Philemon Hou, an actor and singer who was visiting the studio that day, came up with a new melody for the song which became the instrumental hit "Grazing in the Grass."
It was No. 1 on the Billboard pop chart 50 years ago Wednesday.