Have you heard of the Antikythera Mechanism? If so, you will enjoy this beautifully done 3D animation that shows its component parts and functions.
If you haven't heard of the the Antikythera Mechanism, it is an ancient artifact currently housed in the Greek National Archaeological Museum in Athens. The mechanism is a thin metal object that was found by divers in the wreckage of a ancient Roman ship off the coast of Greece in 1900. It was clearly a sophisticated instrument of some kind with a surprisingly modern style gear train. That alone was a startling discovery, but the exact purpose of the machine remained a mystery for a long time.
Recent studies, advances in imaging technology, and painstaking reproductions have led scholars to believe that the device was a form of mechanical computer. The elaborate gear train was used to calculate the movements of stars and planets for points in the past and the future with great accuracy. Scientists and scholars believe it was build around 87 B.C. -- making it one of the most sophisticated ancient devices in existence. According to an article on the Antikythera Mechanism in the journal Nature, its mechanical sophistication would see no equal until mechanical clocks appeared in western Europe in the fourteenth century.
For a more complete story of the Antikythera Mechanism, check out the book Decoding the Heavens: A 2,000-Year-Old Computer--and the Century-long Search to Discover Its Secrets.[ Thanks Joseph! ]