It’s back to Nature in this vehicle called the Naturcar (and Naturtaxi, Naturvan, Naturbus). As you can see from the picture, the source of propulsion is a horse. Not to ride (that would be too much fun) but a horse on a treadmill of sorts.

The vehicle is actually made of mostly glass — let’s not talk about traffic jams caused by staring drivers or what happens in an accident). Passengers ride in the front while the horse does the work in the rear. If the horse stops walking, the conveyor belt / treadmill nudges it back into action. The same belt moves the animal’s "exhaust" out of the horse’s compartment into a holding area beneath the car.

Seems a lot extreme for an innovative idea.