History:
The invention of the thaumatrope, whose name means "turning marvel" or "wonder turner," has often been credited to the astronomer Sir John Herschel.  However, it was a well-known London physicist, Dr. John A. Paris, who made this toy popular.  Thaumatropes were the first of many optical toys, simple devices that continued to provide animated entertainment until the development of modern cinema.

How it works:
A thaumatrope is a small disc, held on opposite sides of its circumference by pieces of string.  An image is drawn on each side of the disc, and is selected in such a way that when the disc is spun, the two images appear to become superimposed. 

Its cool because it makes our eyes look like we are just looking at a picture but for us it look like a video to us but its a picture.