[BroJoeK]

pepsionice: "Somewhere out there....two and three thousand years ago....we had brilliant men...generations ahead of Einstein.
And what they knew....was lost."

Sure, they were smart, as smart as any good mechanical engineer today, no doubt about it.
But they weren't all that freekin smart:

On the Antikythera mechanism:

"Investigations by Freeth and Jones reveal that their simulated mechanism is not particularly accurate, the Mars pointer being up to 38° off at times.
This is not due to inaccuracies in gearing ratios in the mechanism, but rather to inadequacies in the Greek theory at that point in time.
This could not have been improved until first Ptolemy introduced the equant, circa 150 AD, and then when Johannes Kepler changed orbits to ellipses and broke from the concept of uniform motion and circular orbits in 1609 AD.[6]
'In short, the Antikythera Mechanism was a machine designed to predict celestial phenomena according to the sophisticated astronomical theories current in its day, the sole witness to a lost history of brilliant engineering, a conception of pure genius, one of the great wonders of the ancient world — but it didn’t really work very well!' "

[1010RD]

The most striking thing about it is the gear works and the engineering.

[SunkenCiv]

It worked well enough to collect a paycheck, and be long gone after enough years passed to show the error. So, kudos to that ancient engineer! :’)