Scott McKenzie - "San Francisco (Be Sure to Wear Flowers in Your Hair)" (1967)

Well, maybe if John Phillips could write this song in 20 minutes, I can get this blog post out in that amount of time, too.

I think the verses in this song might be constructed such that you don't necessarily notice the demarcation of one ending and another one starting, but there are two verses that start the song. They're metrically squared except for a one-bar dominant prolongation at the end.

Chords one bar each, key of G:

vi - IV - I - V - If you're going to San Francisco
vi - IV - I - V - Be sure to wear some flowers in your hair
vi - I - IV - I - If you're going to San Francisco
I - iii - vi - V (two bars) - You're going to meet some gentle people there

vi - IV - I - V - For those who come to San Francisco
vi - IV - I - V - Summertime will be a love-in there
vi - I - IV - I - In the streets of San Francisco
I - iii - vi - V (two bars) - Gentle people with flowers in their hair

Just a couple of comments here. Putting the tonic chord second in the third line is clever, I think. The plagal cadence that follows it grounds the whole thing in the tonic in a unique way. The vi - V progression at the end is a very soft cadence preparation.

There's a bridge that follows with a prominently featured bVII chord, but when the verse comes back, that's when things suddenly blossom:

vi - ii/IV - I/iii - V - All those who come to San Francisco
vi - IV - I - V - Be sure to wear some flowers in your hair
vi - I - IV - I - If you come to San Francisco
I - iii - vi - I (two bars) - Summertime will be a love-in there

Two new chords introduced in that first line, a ii chord to start the second bar and a iii chord to end the third. They're played like they mean it; it's the most rhythmically dynamic moment in the verses up to that point. The vocal melody here includes an upper neighbor note on G right before those chords that's higher than anything that precedes it and the syllables of "San Francisco" are more empahasized.

The last line is a repeat of line two in the second verse, but set to a different melody here with the different chords. As line four of the verse, it also ends on a tonic chord instead of the dominant heard at the end of verses one and two.

The song ends with a modulation up a whole tone, from a vi chord on E minor to a vi chord on F#, and then an abbreviated verse.

vi - I - IV - I - If you're going to San Francisco
I - iii - vi - I - Summertime will be a love-in there

Notice that, while ostensibly the beginning of a final verse, it actually uses the chords from lines three and four of the previous verses. We end on the tonic chord just like in the third verse, but this time finishing off with a different melodic flourish.

(One final note here - just wanted to mention that the melody throughout the song is pentatonic with the exception of the diatonic bridge. Oh, and I didn't quite get this post done in 20 minutes!)