2,000 Year Old Computer
The Antikythera mechanism is an ancient analogue computer and orrery used to predict astronomical positions and eclipses for calendrical and astrological purposes, as well as the Olympiads, the cycles of the ancient Olympic Games.
- By Marsyas / Wikimedia Commons / CC BY 2.5
Check out this YouTube video about how it was recreated.
It basically shows that our forefathers were very smart indeed.