X-rays and advanced photography have uncovered the true complexity of the mysterious Antikythera mechanism, a device so astonishing that its discovery is like finding a functional Buick in medieval Europe.
Using nothing but an ingenious system of gears, the mechanism could be used to predict the month, day and hour of an eclipse, and even accounted for leap years. It could also predict the positions of the sun and moon against the zodiac, and has a gear train that turns a black and white stone to show the moon's phase on a given date. It is possible that it could also show the astronomical positions of the planets known to the ancients: Mercury, Venus, Mars, Jupiter and Saturn.
It is sad that so many achievements of the ancients were lost for so long; imagine the artifacts and writings that no longer exist at all. Imagine how much we are missing; imagine where humanity would be if they had never been lost to start with.
(thanks to Reddit)