Ah, Labor Day. Americans have marked summer’s unofficial end since 1882, when the holiday was born as a New York City street parade honoring the nation’s working men and women. Through world wars and political tumult, economic downturns and eras of prosperity, the nation’s workers have manufactured, farmed, welded, walked mail routes, driven big rigs, manned oil rigs, re-invented the wheel (a few times), gone digital, and plied a thousand and one other trades. Here, in words and pictures, Fortune teams with LIFE to pay tribute to the sweat, ingenuity, and toil of America’s too-often-unsung workforce.

