Paul McCartney hatches the idea for Sgt. Pepper
On November 19th 1966, on a flight back to London from Nairobi, Paul McCartney came up with the concept for Sgt. Pepper. McCartney and Beatles' roadie Mal Evans earlier flew to Kenya for a safari trip at Ambosali Park near Mount Kilimanjaro.
While there they met up with Paul's then girlfriend Jane Asher. On November 18th they spend the night at a YMCA in Nairobi before flying back to London the following day.
It was on this flight back where McCartney famously hatched the idea for Sgt. Pepper's Lonely Hearts Club Band. The Beatles finished touring earlier that year and were becoming much more involved in studio experimentation and pushing the boundaries of conventional musical traditions.
They had outgrown the clean-cut images of their youth and were fed up being Beatles. Paul had the idea of becoming another band, figuratively speaking.
"We were fed up with being the Beatles. We really hated that fucking four little mop-top boys approach. We were not boys, we were men.
Then suddenly on the plane I got this idea. I thought, Let's not be ourselves. Let's develop alter egos so we're not having to project an image which we know. It would be much more free."