Ancient Computer?

"Computing" covers the advancement of time-keeping techniques, from the classic sundial to Ctesibius's use of constant water flow and primitive gear mechanisms, leading up to what is known as the Antikythera mechanism. An isolated artifact discovered in the wreckage of an ancient cargo vessel, the mechanism's origin and use are largely a mystery, but its elaborate system of gears suggest an advanced early device for calculating the positions of the heavenly bodies.