The opening chord of "A Hard Day's Night," deconstructed...
...via Randy Bachman and Giles (Son of George) Martin.
According to at least one reference book I checked, there's a George Martin piano chord on the original recording somewhere, too.
But in any case, as Bachman says -- isn't that fantastic? I mean, seriously -- after the opening notes of Beethoven's Fifth, is there a more instantly and universally recognizable intro to a piece of music anywhere? I think not.
[h/t jac, satyrical]