3. A 2000 year old computer
It was not until the twenty first century that modern scanning tools finally enabled scientists to penetrate the corrosion and take a look at the insides of the Antikythera Mechanism in 3D. Scanning revealed a set of interlocking gears, similar to those of a clock, as well inscriptions engraved on the inside of the machine, as a kind of instruction manual. Turns out the Antikythera Artifact was an analog machine, or computer, that predated Jesus.
The device enabled users to tell how the skies would look for decades to come, including the positions of the sun and moon, lunar phases, the paths of planets such as Venus, and even eclipses. Several writers from Antiquity, including Cicero, had mentioned the existence of such devices, but the Antikythera Mechanism is the only one ever recovered. Unfortunately, the technology was lost during the Roman era, and the only known sample we know of ended up at the bottom of the sea, its secrets forgotten for over two millennia.
