Universal Constants: A New Foundation of Measurement | NIST    >   Measure - Pursue Accuracy

Boulevard du Temple in Paris, by Daguerre

Made in 1838 by inventor Louis Daguerre, this is believed to be the earliest photograph showing a living person. It is a view of a busy street, but because the exposure lasted for several minutes the moving traffic left no trace. Only the two people near the bottom-left corner stayed in one place long enough to be visible.

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