"Rain" is the title of a 1966 song recorded by the Beatles. It is famous for being the first song to utilize backwards vocals.
Release
The single was first released on May 30, 1966, in the United States and on June 10, 1966 in Britain, as one side of a double A-side single, teamed with "Paperback Writer". "Rain" is not featured on an original album and did not make it onto a compilation album until Past Masters, Volume Two.
The two songs were recorded before the extended sessions for Sgt. Pepper's Lonely Hearts Club Band. "Paperback Writer" was sung live, but "Rain" was studio-only.
Inspiration
The song was originally intended to be rather normal (relative to the other songs at the time). Then one night while stoned John Lennon accidentially played the tapes for "Tomorrow Never Knows", a song on their Revolver album. It played backwards, and with a joint in his mouth Lennon listened to the song. He enjoyed the noise, playing the result to the other Beatles the next day. He then wrote "Rain", and intended to have the song entirely backwards; but George Martin (who claims he discovered the backwards effect) rejected it. So only the final verse was played backwards.
The Verse
Some claim that the song contains a hidden message in the last verse. However, when played backwards one can clearly hear:
Rain
When the rain comes, they run and hide their heads
This is simply the first verse of the song with the word "Rain" sung in front of it (which one would hear after it when backwards).