The Antikythera mechanism, the oldest known surviving geared mechanism, was discovered among artifacts retrieved from a shipwreck off the Greek island of Antikythera.

The Antikythera mechanism is an ancient Greek hand-powered orrery. It is the oldest known example of an analogue computer. It could be used to predict astronomical positions and eclipses decades in advance. It could also be used to track the four-year cycle of athletic games similar to an olympiad, the cycle of the ancient Olympic Games.

A gear or gearwheel is a rotating machine part typically used to transmit rotational motion or torque by means of a series of teeth that engage with compatible teeth of another gear or other part. The teeth can be integral saliences or cavities machined on the part, or separate pegs inserted into it. In the latter case, the gear is usually called a cogwheel. A cog may be one of those pegs or the whole gear. Two or more meshing gears are called a gear train.

The Antikythera wreck is a Roman-era shipwreck dating from the second quarter of the first century BC.

Antikythera or Anticythera, known in antiquity as Aigilia (Αἰγιλία), is a Greek island lying on the edge of the Aegean Sea, between Crete and Peloponnese. Since the 2011 local government reform, it is part of the municipality of Kythira island.