One of the most famous poems of the last half-century must be Philip Larkin's "Annus Mirabilis." Its first stanza goes:
Sexual intercourse began
In nineteen sixty-three
(Which was rather late for me) ---
Between the end of the Chatterley ban
And the Beatles' first LP.
Re-reading it recently, I was struck by an odd thought: If the editor of some 22nd-century edition of Larkin's verse feels the need to annotate this poem, he or she probably won't need to footnote "the Beatles," but will feel called upon to explain what an LP is.