In 1965, George Martin called a Beatles song a “problem”. It’s now been streamed over 1,000,000,000 times

Paul McCartney’s “Yesterday” challenged the Beatles’ usual rock band sound because it was a delicate ballad intended to feature one Beatle alone. Producer George Martin called it a problem, but the recording’s string arrangement helped turn that challenge into one of the group’s best-known songs.

Martin said the song did not fit the pattern of two guitars, bass and drums, so he drew on his arranging experience. McCartney proposed using a seventh interval in the outro, and the finished track features his solo performance with strings. The headline says “Yesterday” has now been streamed more than one billion times.