The ultimate example of producer Phil Spector's "Wall of Sound" technique -- a dense, layered effect that reproduced well on AM radio and jukeboxes. Spector himself called his technique "a Wagnerian approach to rock & roll: little symphonies for the kids."

This song was a shocking 43 seconds longer than the strict 3 minute time-limit imposed by 1965 radio on pop singles. It went to #1 anyway, and remains the most played song in radio history.