The Antikythera Mechanism

Recovered from a Roman shipwreck at the turn of the last century, this bronze and wood device turned out to be a complex computer for calculating the relative position of the sun, the moon and the planet built by the ancient Greeks in the second century BC. According the the New Zeland Herald, on its finding:

"the device was evidently an instrument of some sort because it used a complicated set of gears to move a series of concentric wheels and pointers which appeared to predict the movements of astronomical objects.

However, the scientists were surprised to find that the machine was in fact a sophisticated analogue computer that acted as a long-term calendar for predicting lunar and solar eclipses as well as the movements of the planets."

The most amazing part of the story is that the Mechnaism's function was still discernible after having spent 2000 years submerged under 40+ meters of water. Is there anything you've made that could survive something like that? Is there something you could design and build that might be able to?