On this day in 1967, The Beatles earned their 15th US number one hit with Hello Goodbye

Written by Paul McCartney in September, the song explores themes of duality in its lyrics. To compose the lyrics, McCartney reportedly sat at a piano and asked Beatles aide Alistair Taylor to say the opposite of whatever he said.

Within a month, the band headed to Abbey Road Studios (formerly EMI studios) to record the song, ready to be released in late November. The song was released as a single, with Lennon’s I Am the Walrus on the B-side. Lennon had requested his song on the A-side, but it was decided Hello Goodbye would be a more commercially viable option.

Critics were harsh on the song, but the public reception soon proved that the track had more staying power than was thought. On its first day of release in Britain, the song sold over 300,000 copies and it soon went on to top charts in Britain as well as the US, Canada, Australia, Germany, Holland and Norway. Hello Goodbye is still considered one of the most popular and well-known songs from the band, appearing on numerous compilations and greatest hits album to this day.