Mystery-drive mechanical or electromechanical timepiece

A mechanical or electromechanical timepiece comprising a watch case delimiting an internal volume, said watch case comprising:

• a back delimiting the watch case at a bottom;
• a crystal closing the watch case at a top, said crystal defining a useful display aperture;
• a middle part connecting the back and the crystal to one another;
• a horological movement housed in the internal volume of the watch case;
• a first hand for displaying information fastened onto a first pipe, said first hand being visible via the useful display aperture and being rotated with respect to the watch case by the horological movement with a first driving belt extending at least partially in the useful display aperture;
• and
• a second hand for displaying information fastened to a second pipe is arranged in the useful display aperture and is rotated with respect to the watch case by the horological movement with a second driving belt extending at least partially in the useful display aperture,
• wherein the timepiece comprises the internal volume of the watch case filled with a fluid wherein the first and second driving belts are submerged, and wherein the first and second driving belts are made of a material whose optical refractive index is equal or substantially equal to that of the fluid,
• wherein a first end portion connecting each of the first hand and the second hand to the first pipe and second pipe respectively, is made of a material wherein the optical refractive index of the portion is the same as or similar to the optical refractive index of the fluid such that only a second end portion of each of the first hand and second hand is visible.