An ancient Greek analogue computer used to predict astronomical positions and eclipses for calendar and astrological purposes decades in advance.
The artifact was retrieved from the sea in 1901, and identified on 17 May 1902 as containing a gear wheel by archaeologist Valerios Stais, among wreckage retrieved from a wreck off the coast of the Greek island Antikythera. The instrument is believed to have been designed and constructed by Greek scientists and has been variously dated to about 87 BC, or between 150 and 100 BC, or to 205 BC, or to within a generation before the shipwreck, which has been dated to approximately 70-60 BC.