These images off How To Be A Retronaut were taken by Lewis Hine back in the 1900s and have been recently released by the National Child Labor Committee Collection at the Library of Congress. How far we’ve come, at least in some parts of the world, that this industry is no longer able to exploit children in this way.
There isn’t much to be said about these photos, they speak for themselves. I find myself revisiting them every other week or so just to be reminded of their brilliance. The photographer, Prokudin-Gorskii, developed an insanely ingenious technique that was worlds ahead of its time. Here’s a pretty detailed description of the RGB process.