The Antikythera mechanism (/?ænt?k?????r?/ AN-tih-kih-THEER-?) is an ancient Greek hand-powered orrery, described as the oldest example of an analogue computer [1][2][3] used to predict astronomical positions and eclipses decades in advance. [4][5][6] It could also be used to track the four-year cycle of athletic games which was similar to an Olympiad, the cycle of the ancient Olympic Games. [7][8] [9] This artefact was among wreckage retrieved from a shipwreck off the coast of the Greek island Antikythera in 1901.[10][11] On 17 May 1902 it was identified as containing a gear by archaeologist Valerios Stais.