From the introduction to Jo Marchant's "Decoding the Heavens":
In 1900 a group of sponge divers blown off course in the Mediterranean discovered an Ancient Greek shipwreck dating from around 70 BC.
Lying unnoticed for months amongst their hard-won haul was what appeared to be a formless lump of corroded rock. It turned out to be the most stunning scientific artefact we have from antiquity. For more than a century this 'Antikythera mechanism' puzzled academics. It was ancient clockwork, unmatched in complexity for 1000 years - but who could have made it, and what was it for?
Now, more than 2000 years after the device was lost at sea, scientists have pieced together its intricate workings and revealed its secrets. The Antikythera Mechanism is an ancient Greek artefact comprising more than 30 precisely cut bronze gear wheels, dials and pointers held in a wooden case. It was probably one among many luxury gadgets for the educated Greek and Roman elite — the only example of its kind to survive. "The Antikythera Mechanism," Marchant concludes, "was originally meant as a celebration of the heavens."