If it weren't for a highly dutiful recording engineer, one of the most famous hidden tracks of all time might have never been heard by anyone outside of the Beatles' inner circle. Paul McCartney recorded the 23-second 'Her Majesty' for inclusion on 'Abbey Road''s closing multi-song medley. It was meant to be placed between 'Mean Mr. Mustard' and 'Polythene Pam' -- you can hear how it might have sounded here.

However, McCartney decided he didn't like the track and ordered John Kurlander to throw it away. Luckily, the engineer had been told to never throw away any Beatles music, and tacked it to the end of a rough edit. When the band heard it the next day, they decided to keep the happy accident on the final album.