The Antikythera mechanism is the most technologically complex object ever found from the ancient world. Dating back to between 205 and 60 B.C.E., this magnificent bronze device contains dozens of small gears with teeth about a millimeter long that were used to predict the position and calculate the variable motion of the moon. The ancient Greeks may did not know about elliptical orbits, yet they explained the moon’s subtle motion by combining two circular motions in what is called an epicyclic theory! These gears could also predict the position of the sun and the planets at any chosen time. Crazy, huh? The Antikythera mechanism is an Ancient Greek hand-powered orrery, described as the oldest known example of an analogue computer used to predict astronomical positions and eclipses decades in advance. No wonder Greeks were, and still are, innovative!