"I Left My Heart In San Francisco" is a song most famously sung by Tony Bennett. At 2:52 (in my version), it serves as a double paean to the city of San Francisco, as well as to the singer's love "in San Francisco". The song begins with Bennett softly crooning, comparing it favorably to Paris, Rome and New York City, and gradually swells and builds as Bennett describes the city and his plans to return.
It is pretty simple. The music starts at a pitter-patter and builds to a crescendo as the accompaniment becomes more and more lush. To a modern listener, some of this might seem a little bit corny: the extravagant orchestration and soaring vocals sound overdone to post-rock ears. But even the most dour commentator who doesn't like this type of music would have to acknowledge that, for its style, it is skillfully and artistically done. Tony Bennett really knows how to sing, is what I am saying here.
Also, interestingly, the version I have of the single was backed by "I Wanna Be Around", which, while it has a similar musical style, has a bit more swing in it than the A-Side.