The Antikythera Mechanism

The Antikythera Mechanism is a 2000 year old
device discovered by sponge divers near a Greek island.
The best guess is that it is a mechanical
analog computer that can calculate the position
of the sun, moon and planets.

By a weird synchronicity, I first learned of it
on Serendipita, a blog I occasionally visit.
The next day it was mentioned on SolderSmoke #44.