The origin of "the shot heard round the world", from Ralph Waldo Emerson's "concord hymn".
The phrase has taken on different meanings over time, but I have to believe Q is referring to the first shot of the American Revolution.
Apologies if this has been posted, busyfag here. It's inspiring nonetheless.
By the rude bridge that arched the flood,
Their flag to April’s breeze unfurled,
Here once the embattled farmers stood,
And fired the shot heard round the world.
The foe long since in silence slept;
Alike the conqueror silent sleeps;
And Time the ruined bridge has swept
Down the dark stream which seaward creeps.
On this green bank, by this soft stream,
We set to-day a votive stone;
That memory may their deed redeem,
When, like our sires, our sons are gone.
Spirit, that made those heroes dare,
To die, and leave their children free,
Bid Time and Nature gently spare
The shaft we raise to them and thee.