Antikythera Mechanism
The account
An analog computer so advanced that it could only have come from a lost civilization or from visitors from the stars.
What investigators found
Built by Greeks using Babylonian astronomical data. It predicted eclipses, the phases of the Moon and the Olympic calendar with dozens of bronze gears.
The story
At Easter in 1900, sponge divers from the island of Symi took shelter from a storm near Antikythera, between Crete and the Peloponnese. On the seabed, about 45 meters down, they found a Roman ship that had sunk around 70 to 60 BC, loaded with statues, jewelry and pottery.
Among the recovered objects was a lump of bronze and wood that nobody paid much attention to. In 1902, archaeologist Valerios Stais noticed a toothed wheel in it. Decades of study, and CT scans carried out from 2005 onward, revealed at least 30 gears and thousands of engraved Greek letters.
The device, about the size of a shoebox, showed the positions of the Sun and the Moon, tracked the lunar phases, predicted eclipses and kept the calendar of the Olympic Games. Nothing this complex appears again for more than a thousand years. Who built it, and why no other one survived, is still unanswered.