Movies that capture the essence of a time period

[floridaswamprat]

I was watching Almost Famous for the umpteen time the other day and commented to my wife that I felt it captured the essence of that early seventies time period perfectly (my adolescent years).

I was curious as to what other movies capture the essence of a period. Not just taking place during a certain era, but one that exemplifies that era.

Another that I believe does (though it was a touch before my cognitive time - I was born in 1960) is American Graffiti.

Coincidentally, both these movies strongly emphasis the role of music in an era.

So . . . what are your thoughts as to other movies that capture that essence of a time?