The Antikythera Mechanism: ancient mechanical astrological calendar, & reminder of the fragility of knowledge.
3D Simulation of one theoretical configuration of the mechanism’s gears - http://demonstrations.wolfram.com/AntikytheraMechanism/
The Antikythera Mechanism Research Project - http://www.antikythera-mechanism.gr/
Random Wikipedia Page - https://en.wikipedia.org/wiki/Special:Random