A video clip of a guy trying to build a working telegraph using only Stone Age materials. It’s a bit of a stretch to claim that he’s successful, and he does cheat by using a cigarette lighter and (I think) charcoal briquettes to smelt copper and iron ores. But it’s still pretty cool that he manages to produce a working battery (for some definition of “working”) with iron and copper he smelted himself, and cattail roots.
Good thing he doesn’t have to do this in a hurry, with a lizard-like alien trying to kill him.