Arguably, Lewis Hine has a lot of incredibly famous photographs. However, the one everyone would recognize if they saw it would be his photograph entitled “Power House Mechanic Working on Steam Pump”. A lot of people think of the “Mother Migrant” photo when they think of Great Depression photos, but this was taken by Dorothea Lange, not Lewis Hine. (I made the same mistake looking for the answer to this question.) His most famous photograph shows a man, thin enough you can almost see his ribs, working on a steam engine.
He’s holding a large wrench, working at a bolt. We don’t know if the worker ever gets the bolt off, but we can tell that if he makes a wrong move, or that steam engine starts up, he could be seriously hurt.