Which ancient computer was recovered from a Greek shipwreck?

The Antikythera mechanism is an ancient Greek hand-powered orrery built in the 2nd century BC and discovered in 1901. 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.