The Antikythera Mechanism is an ancient artifact, found in a sail wreck near the Greek island of Crete, in 1901. After years of research, the scientists understood how it worked and what it was used for: it is the first analog computing device!
Consisting of several dials and gears, it can track planetary movements, solar & lunar eclipses, the constellations of the zodiac; it also tracks leap years, the cycle of the Olympic games, the lunar phases, and many other things. Why it was useful and what was it used for remains a mystery, though.
Its mechanical parts work on the principle of differential gears, a "technology" that was not seen before the 17th century... but this device is dated to the 2nd Century BC!!! That's a gap of 1700 years...
There is also an official scientific Research Project to reveal all secrets of the Mechanism. Anyway, this is a rendering of the weird parts of this amazing device:
Antikythera Mechanism
by
A fractal made in JWildFire
(right-click -> "open in new tab" for detailed view)