I've got a soft place for mechanical watches, and that's why the so-known as Sistem51 (Piece of fabric calls it the shouty SISTEM51) is really near and dear to me. It's, in a nutshell, probably the most interesting developments in mass-market micro mechanics because the invention from the quarta movement Timex. It's a mixture of awesome high-tech and absurd, Tamagotchi-like old tech, and it is interesting it hasn’t been covered more.
A mechanical watch is powered exclusively with a mainspring, without needing electric power. Inside a hand-wound mechanical watch, the movement's mainspring is wound by winding the crown. The mainspring of the self-winding mechanical watch is wound through the movement of the arm which it's worn and stores energy.