Under 45 metres of water, just off the Greek Island of Antikythera is an Ancient Greek shipwreck, discovered within the sunken ship was the Antikuthera Mechanism. A mechanism that is thought to of been used to calculate astronomical positions. However this ancient calculator is very significant due to the fact that it’s as complex as an 18th century top-notch clock, yet was built between 150 to 100 BCE.
It’s an ancient analog computer that consists of a box with dials on the outside and a very complex assembly of about 30 bronze gear wheels mounted inside, nothing similar to this has ever been discovered or is mentioned in any known writings from the period of its creation. The reason that this mechanism is so mysterious is that it can predict astronomical positions and eclipses for calendrical and astrological purposes, as well as the cycles of Olympic Games.